diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..46f1c90
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,13 @@
+version: 2
+updates:
+  - package-ecosystem: bundler
+    directory: "/"
+    schedule:
+      interval: "daily"
+    open-pull-requests-limit: 10
+    ignore:
+      - dependency-name: "rubocop-lts"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
new file mode 100644
index 0000000..502c2a0
--- /dev/null
+++ b/.github/workflows/codeql-analysis.yml
@@ -0,0 +1,70 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+#
+# ******** NOTE ********
+# We have attempted to detect the languages in your repository. Please check
+# the `language` matrix defined below to confirm you have the correct set of
+# supported CodeQL languages.
+#
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ main, "*-stable" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ main, "*-stable" ]
+  schedule:
+    - cron: '35 1 * * 5'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'ruby' ]
+        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
+        # Learn more about CodeQL language support at https://git.io/codeql-language-support
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v3
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v3
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 https://git.io/JvXDl
+
+    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+    #    and modify them (or add more) to build your code if your project
+    #    uses a compiled language
+
+    #- run: |
+    #   make bootstrap
+    #   make release
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v3
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
new file mode 100644
index 0000000..6306958
--- /dev/null
+++ b/.github/workflows/coverage.yml
@@ -0,0 +1,121 @@
+name: Test Coverage
+
+env:
+  K_SOUP_COV_MIN_BRANCH: 80
+  K_SOUP_COV_MIN_LINE: 91
+  K_SOUP_COV_MIN_HARD: true
+  K_SOUP_COV_DO: true
+  K_SOUP_COV_COMMAND_NAME: "RSpec Coverage"
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Specs with Coverage - Ruby ${{ matrix.ruby }} ${{ matrix.name_extra || '' }}
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Coverage
+          - ruby: "3.4"
+            appraisal: "coverage"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+    steps:
+      - uses: amancevice/setup-code-climate@v2
+        name: CodeClimate Install
+        if: ${{ github.event_name != 'pull_request' }}
+        with:
+          cc_test_reporter_id: ${{ secrets.CC_TEST_REPORTER_ID }}
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "${{ matrix.ruby }}"
+          rubygems: "${{ matrix.rubygems }}"
+          bundler: "${{ matrix.bundler }}"
+          bundler-cache: false
+
+      - name: CodeClimate Pre-build Notification
+        run: cc-test-reporter before-build
+        if: ${{ github.event_name != 'pull_request' }}
+        continue-on-error: ${{ matrix.experimental != 'false' }}
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
+
+      - name: CodeClimate Post-build Notification
+        run: cc-test-reporter after-build
+        if: ${{ github.event_name != 'pull_request' }}
+        continue-on-error: ${{ matrix.experimental != 'false' }}
+
+      - name: Code Coverage Summary Report
+        uses: irongut/CodeCoverageSummary@v1.3.0
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          filename: ./coverage/coverage.xml
+          badge: true
+          fail_below_min: true
+          format: markdown
+          hide_branch_rate: false
+          hide_complexity: true
+          indicators: true
+          output: both
+          thresholds: '69 80'
+        continue-on-error: ${{ matrix.experimental != 'false' }}
+
+      - name: Add Coverage PR Comment
+        uses: marocchino/sticky-pull-request-comment@v2
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          recreate: true
+          path: code-coverage-results.md
+        continue-on-error: ${{ matrix.experimental != 'false' }}
+
+      - name: Coveralls
+        uses: coverallsapp/github-action@master
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+        continue-on-error: ${{ matrix.experimental != 'false' }}
+
+      - name: Upload results to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.github/workflows/dependency-review.yml b/.github/workflows/dependency-review.yml
new file mode 100644
index 0000000..0d4a013
--- /dev/null
+++ b/.github/workflows/dependency-review.yml
@@ -0,0 +1,20 @@
+# Dependency Review Action
+#
+# This Action will scan dependency manifest files that change as part of a Pull Request, surfacing known-vulnerable versions of the packages declared or updated in the PR. Once installed, if the workflow run is marked as required, PRs introducing known-vulnerable packages will be blocked from merging.
+#
+# Source repository: https://github.com/actions/dependency-review-action
+# Public documentation: https://docs.github.com/en/code-security/supply-chain-security/understanding-your-software-supply-chain/about-dependency-review#dependency-review-enforcement
+name: 'Dependency Review'
+on: [pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  dependency-review:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout Repository'
+        uses: actions/checkout@v4
+      - name: 'Dependency Review'
+        uses: actions/dependency-review-action@v4
diff --git a/.github/workflows/heads.yml b/.github/workflows/heads.yml
new file mode 100644
index 0000000..f528289
--- /dev/null
+++ b/.github/workflows/heads.yml
@@ -0,0 +1,84 @@
+name: Heads Compat Matrix
+
+env:
+  K_SOUP_COV_DO: false
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Specs - Ruby ${{ matrix.ruby }} ${{ matrix.appraisal }}${{ matrix.name_extra || '' }}
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      fail-fast: true
+      matrix:
+        include:
+          # ruby-head
+          - ruby: "ruby-head"
+            appraisal: "ruby-head"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+          # truffleruby-head
+          - ruby: "truffleruby-head"
+            appraisal: "truffleruby-head"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+          # jruby-head
+          # Error output has a significantly different format in JRuby :(
+          #  - ruby: "jruby-head"
+          #    appraisal: "jruby-head"
+          #    exec_cmd: "turbo_tests -n4"
+          #    gemfile: "Appraisal.root"
+          #    rubygems: latest
+          #    bundler: latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler: ${{ matrix.bundler }}
+          bundler-cache: false
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
diff --git a/.github/workflows/legacy.yml b/.github/workflows/legacy.yml
new file mode 100644
index 0000000..f2dc030
--- /dev/null
+++ b/.github/workflows/legacy.yml
@@ -0,0 +1,67 @@
+name: Legacy Compat (EOL, Ruby 3.0) Matrix
+
+env:
+  K_SOUP_COV_DO: false
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Specs - Ruby ${{ matrix.ruby }} ${{ matrix.appraisal }}${{ matrix.name_extra || '' }}
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-22.04
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Ruby 3.0
+          - ruby: "3.0"
+            appraisal: "ruby-3-0"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: '3.5.23'
+            bundler: '2.5.23'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler: ${{ matrix.bundler }}
+          bundler-cache: false
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
diff --git a/.github/workflows/style.yml b/.github/workflows/style.yml
new file mode 100644
index 0000000..62cbe81
--- /dev/null
+++ b/.github/workflows/style.yml
@@ -0,0 +1,64 @@
+name: Ruby - Style
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  rubocop:
+    name: RuboCop Gradual
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Style
+          - ruby: "3.4"
+            appraisal: "style"
+            exec_cmd: "rake rubocop_gradual:check"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler: ${{ matrix.bundler }}
+          bundler-cache: false
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
diff --git a/.github/workflows/supported.yml b/.github/workflows/supported.yml
new file mode 100644
index 0000000..062faf0
--- /dev/null
+++ b/.github/workflows/supported.yml
@@ -0,0 +1,90 @@
+name: Supported Compat Matrix
+
+env:
+  K_SOUP_COV_DO: false
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Specs - Ruby ${{ matrix.ruby }} ${{ matrix.appraisal }}${{ matrix.name_extra || '' }}
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      matrix:
+        include:
+          # Ruby 3.1
+          - ruby: "3.1"
+            appraisal: "ruby-3-1"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+          # Ruby 3.2
+          - ruby: "3.2"
+            appraisal: "ruby-3-2"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+          # Ruby 3.3
+          - ruby: "3.3"
+            appraisal: "ruby-3-3"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+          # Ruby 3.4
+          - ruby: "3.4"
+            appraisal: "ruby-3-4"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: latest
+            bundler: latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler: ${{ matrix.bundler }}
+          bundler-cache: false
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
diff --git a/.github/workflows/tag_and_release.yml b/.github/workflows/tag_and_release.yml
index 9d0264a..96712c2 100644
--- a/.github/workflows/tag_and_release.yml
+++ b/.github/workflows/tag_and_release.yml
@@ -20,7 +20,7 @@ jobs:
       packages: write
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Ruby 2.7
       uses: ruby/setup-ruby@v1
       with:
@@ -33,7 +33,7 @@ jobs:
         bundle install
         bundle exec turbo_tests
 
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: "ruby-gem"
         path: "pkg/*.gem"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 657d595..4f56ce7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -2,6 +2,8 @@ name: Tests
 
 on:
   pull_request:
+    branches:
+      - '!*' # Ignore this workflow; Remove workflow once done pulling in upstream PRs
 
 permissions:
   contents: read
@@ -17,7 +19,7 @@ jobs:
         os: [ ubuntu-latest, windows-latest ]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{matrix.ruby}}
diff --git a/.github/workflows/unsupported.yml b/.github/workflows/unsupported.yml
new file mode 100644
index 0000000..494818a
--- /dev/null
+++ b/.github/workflows/unsupported.yml
@@ -0,0 +1,67 @@
+name: Unsupported Compat (EOL, Ruby 2.7) Matrix
+
+env:
+  K_SOUP_COV_DO: false
+
+on:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '!*' # Do not execute on tags
+  pull_request:
+    branches:
+      - '*'
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Specs - Ruby ${{ matrix.ruby }} ${{ matrix.appraisal }}${{ matrix.name_extra || '' }}
+    if: "!contains(github.event.commits[0].message, '[ci skip]') && !contains(github.event.commits[0].message, '[skip ci]')"
+    runs-on: ubuntu-22.04
+    continue-on-error: ${{ matrix.experimental || endsWith(matrix.ruby, 'head') }}
+    env: # $BUNDLE_GEMFILE must be set at job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/${{ matrix.gemfile }}.gemfile
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Ruby 2.7
+          - ruby: "2.7"
+            appraisal: "ruby-2-7"
+            exec_cmd: "turbo_tests -n4"
+            gemfile: "Appraisal.root"
+            rubygems: '3.4.22'
+            bundler: '2.4.22'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby & RubyGems
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler: ${{ matrix.bundler }}
+          bundler-cache: false
+
+      # Raw `bundle` will use the BUNDLE_GEMFILE set to matrix.gemfile (i.e. Appraisal.root)
+      # We need to do this first to get appraisal installed.
+      # NOTE: This does not use the main Gemfile at all.
+      - name: Bundle install for Appraisal ${{ matrix.appraisal }}
+        run: bundle
+      - name: Install Appraisal ${{ matrix.appraisal }} dependencies
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle
+      - name: Run ${{ matrix.appraisal }} tests via ${{ matrix.exec_cmd }}
+        run: bundle exec appraisal ${{ matrix.appraisal }} bundle exec ${{ matrix.exec_cmd }}
diff --git a/.gitignore b/.gitignore
index 2a71158..2fde0d5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -66,3 +66,7 @@ tags
 
 # End of https://www.toptal.com/developers/gitignore/api/macos,vim
 
+# Appraisals Bundles (only commit the coverage, audit, and style lockfiles)
+gemfiles/ruby_*.gemfile.lock
+gemfiles/*_head.gemfile.lock
+Appraisal.root.gemfile.lock
\ No newline at end of file
diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..eb389b5
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,5 @@
+inherit_gem:
+  rubocop-lts: config/rubygem_rspec.yml
+
+require:
+  - 'rubocop-packaging'
diff --git a/.rubocop_gradual.lock b/.rubocop_gradual.lock
new file mode 100644
index 0000000..eea178e
--- /dev/null
+++ b/.rubocop_gradual.lock
@@ -0,0 +1,65 @@
+{
+  "fixtures/rspec/errors_outside_of_examples_spec.rb:2409688709": [
+    [1, 16, 54, "RSpec/DescribeClass: The first argument to describe should be the class or module being tested.", 3626965792],
+    [2, 35, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885]
+  ],
+  "fixtures/rspec/failing_spec.rb:1154565131": [
+    [1, 16, 23, "RSpec/DescribeClass: The first argument to describe should be the class or module being tested.", 986317040],
+    [11, 12, 1, "RSpec/ExpectActual: Provide the actual value you are testing to `expect(...)`.", 177559]
+  ],
+  "fixtures/rspec/no_method_error_spec.rb:47614094": [
+    [1, 16, 20, "RSpec/DescribeClass: The first argument to describe should be the class or module being tested.", 4112385446]
+  ],
+  "fixtures/rspec/pending_exceptions_spec.rb:2868747541": [
+    [1, 16, 51, "RSpec/DescribeClass: The first argument to describe should be the class or module being tested.", 4038399051],
+    [5, 12, 1, "RSpec/ExpectActual: Provide the actual value you are testing to `expect(...)`.", 177559],
+    [9, 12, 3, "RSpec/ExpectActual: Provide the actual value you are testing to `expect(...)`.", 193358996],
+    [12, 3, 43, "RSpec/PendingWithoutReason: Give the reason for xit.", 1479957056],
+    [13, 12, 1, "RSpec/ExpectActual: Provide the actual value you are testing to `expect(...)`.", 177556]
+  ],
+  "lib/turbo_tests.rb:2945832194": [
+    [23, 5, 323, "Style/ClassMethodsDefinitions: Use `class << self` to define a class method.", 166166262],
+    [50, 5, 269, "Style/ClassMethodsDefinitions: Use `class << self` to define a class method.", 4255608859],
+    [71, 5, 614, "Style/ClassMethodsDefinitions: Use `class << self` to define a class method.", 574527918]
+  ],
+  "lib/turbo_tests/runner.rb:3014787945": [
+    [12, 5, 479, "Style/ClassMethodsDefinitions: Use `class << self` to define a class method.", 1520723843],
+    [23, 5, 1400, "Style/ClassMethodsDefinitions: Use `class << self` to define a class method.", 1925027850],
+    [240, 11, 10, "ThreadSafety/NewThread: Avoid starting new threads.", 3411682361],
+    [259, 47, 6, "Style/GlobalStdStream: Use `$stderr` instead of `STDERR`.", 3356712163],
+    [261, 21, 10, "ThreadSafety/NewThread: Avoid starting new threads.", 3411682361],
+    [270, 7, 10, "ThreadSafety/NewThread: Avoid starting new threads.", 3411682361],
+    [330, 9, 6, "Style/GlobalStdStream: Use `$stdout` instead of `STDOUT`.", 3356722952]
+  ],
+  "spec/cli_spec.rb:3990998076": [
+    [1, 1, 30, "RSpec/SpecFilePathFormat: Spec path should end with `turbo_tests/cli*_spec.rb`.", 965721356],
+    [11, 13, 28, "RSpec/ContextWording: Context description should match /^when\\b/, /^with\\b/, or /^without\\b/.", 2146945865],
+    [30, 7, 12, "RSpec/MultipleExpectations: Example has too many expectations [3/1].", 2388739333],
+    [31, 34, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885],
+    [38, 13, 20, "RSpec/ContextWording: Context description should match /^when\\b/, /^with\\b/, or /^without\\b/.", 812172126],
+    [41, 7, 632, "RSpec/ExampleLength: Example has too many lines. [10/5]", 4177603105],
+    [42, 34, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885],
+    [60, 13, 28, "RSpec/ContextWording: Context description should match /^when\\b/, /^with\\b/, or /^without\\b/.", 2146945865],
+    [75, 7, 12, "RSpec/MultipleExpectations: Example has too many expectations [3/1].", 2388739333],
+    [76, 34, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885],
+    [87, 13, 20, "RSpec/ContextWording: Context description should match /^when\\b/, /^with\\b/, or /^without\\b/.", 812172126],
+    [90, 7, 600, "RSpec/ExampleLength: Example has too many lines. [10/5]", 1660729462],
+    [91, 34, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885],
+    [111, 5, 32, "RSpec/MultipleExpectations: Example has too many expectations [2/1].", 281328851],
+    [112, 32, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885],
+    [121, 5, 38, "RSpec/MultipleExpectations: Example has too many expectations [2/1].", 3463001811],
+    [121, 5, 409, "RSpec/ExampleLength: Example has too many lines. [9/5]", 4122755410],
+    [122, 32, 3, "RSpec/BeEql: Prefer `be` over `eql`.", 193405885]
+  ],
+  "spec/doc_formatter_spec.rb:233381593": [
+    [5, 16, 19, "RSpec/DescribeClass: The first argument to describe should be the class or module being tested.", 879596202]
+  ],
+  "spec/turbo_tests_spec.rb:811756577": [
+    [10, 15, 7, "RSpec/MessageSpies: Prefer `have_received` for setting message expectations. Setup `ParallelTests::Tasks` as a spy using `allow` or `instance_spy`.", 1384559950],
+    [20, 15, 7, "RSpec/MessageSpies: Prefer `have_received` for setting message expectations. Setup `ParallelTests::Tasks` as a spy using `allow` or `instance_spy`.", 1384559950]
+  ],
+  "turbo_tests.gemspec:2921004918": [
+    [29, 16, 36, "ThreadSafety/DirChdir: Avoid using `Dir.chdir` due to its process-wide effect.", 3576345059],
+    [30, 5, 19, "Packaging/GemspecGit: Avoid using git to produce lists of files. Downstreams often need to build your package in an environment that does not have git (on purpose). Use some pure Ruby alternative, like `Dir` or `Dir.glob`.", 3879951891]
+  ]
+}
diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..041df9a
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1 @@
+ruby 3.4.1
diff --git a/Appraisal.root.gemfile b/Appraisal.root.gemfile
new file mode 100644
index 0000000..c5db382
--- /dev/null
+++ b/Appraisal.root.gemfile
@@ -0,0 +1,12 @@
+git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }
+
+source "https://rubygems.org"
+
+# Appraisal Root Gemfile is for running appraisal to generate the Appraisal Gemfiles
+#   in gemfiles/*gemfile.
+# On CI, we use it for the Appraisal-based builds.
+# We do not load the standard Gemfile, as it is tailored for local development.
+
+gemspec
+
+gem "appraisal", github: "pboling/appraisal", branch: "eval_gemfile"
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 0000000..f24e85e
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+appraise "ruby-2-7" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-3-0" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-3-1" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-3-2" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-3-3" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-3-4" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+# Only run security audit on latest Ruby version
+appraise "audit" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  eval_gemfile "modular/audit.gemfile"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+# Only run coverage on latest Ruby version
+appraise "coverage" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  eval_gemfile "modular/coverage.gemfile"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+# Only run linter on latest Ruby version (but, in support of oldest supported Ruby version)
+appraise "style" do
+  gem "mutex_m", "~> 0.2"
+  gem "stringio", "~> 3.0"
+  eval_gemfile "modular/style.gemfile"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "ruby-head" do
+  gem "mutex_m", ">= 0.2"
+  gem "stringio", ">= 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "truffleruby-head" do
+  gem "mutex_m", ">= 0.2"
+  gem "stringio", ">= 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
+
+appraise "jruby-head" do
+  gem "mutex_m", ">= 0.2"
+  gem "stringio", ">= 3.0"
+  remove_gem "appraisal" # only present because it must be in the gemfile because we target a git branch
+end
diff --git a/Gemfile b/Gemfile
index 3085f59..7203c89 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,27 @@
 source "https://rubygems.org"
 
-# Specify your gem's dependencies in turbo_tests.gemspec
+#### IMPORTANT #######################################################
+# Gemfile is for local development ONLY; Gemfile is NOT loaded in CI #
+####################################################### IMPORTANT ####
+
+# Specify your gem's general development dependencies in turbo_tests.gemspec
 gemspec
 
-gem "rake", "~> 13.0"
+# Security Audit
+if RUBY_VERSION >= "3"
+  # NOTE: Audit fails on Ruby 2.7 because nokogiri has dropped support for Ruby < 3
+  # See: https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-r95h-9x8f-r3f7
+  # We can't add upgraded nokogiri here unless we are developing on Ruby 3+
+  eval_gemfile "gemfiles/modular/audit.gemfile"
+end
+
+# Code Coverage
+eval_gemfile "gemfiles/modular/coverage.gemfile"
+
+# Linting
+eval_gemfile "gemfiles/modular/style.gemfile"
+
+# Documentation
+eval_gemfile "gemfiles/modular/documentation.gemfile"
+
+gem "appraisal", path: "/Users/pboling/src/forks/appraisal"
diff --git a/Gemfile.lock b/Gemfile.lock
index a95169f..f6383e4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,40 +5,191 @@ PATH
       parallel_tests (>= 3.3.0, < 5)
       rspec (>= 3.10)
 
+PATH
+  remote: /Users/pboling/src/forks/appraisal
+  specs:
+    appraisal (3.0.0.rc1)
+      bundler
+      rake
+      thor (>= 0.14.0)
+
 GEM
   remote: https://rubygems.org/
   specs:
+    ansi (1.5.0)
+    ast (2.4.2)
+    backports (3.25.0)
+    benchmark (0.4.0)
+    bundler-audit (0.9.2)
+      bundler (>= 1.2.0, < 3)
+      thor (~> 1.0)
     coderay (1.1.3)
-    diff-lcs (1.5.0)
-    method_source (1.0.0)
-    parallel (1.22.1)
-    parallel_tests (4.2.0)
+    date (3.4.1)
+    diff-lcs (1.5.1)
+    diffy (3.4.3)
+    docile (1.4.1)
+    github-markup (5.0.1)
+    json (2.9.1)
+    kettle-soup-cover (1.0.4)
+      simplecov (~> 0.22)
+      simplecov-cobertura (~> 2.1)
+      simplecov-console (~> 0.9, >= 0.9.1)
+      simplecov-html (~> 0.12)
+      simplecov-lcov (~> 0.8)
+      simplecov-rcov (~> 0.3, >= 0.3.3)
+      simplecov_json_formatter (~> 0.1, >= 0.1.4)
+      version_gem (~> 1.1, >= 1.1.4)
+    language_server-protocol (3.17.0.4)
+    lint_roller (1.1.0)
+    method_source (1.1.0)
+    ostruct (0.6.1)
+    parallel (1.26.3)
+    parallel_tests (4.9.0)
       parallel
-    pry (0.14.2)
+    parser (3.3.7.0)
+      ast (~> 2.4.1)
+      racc
+    pry (0.15.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    rake (13.0.6)
-    rspec (3.12.0)
-      rspec-core (~> 3.12.0)
-      rspec-expectations (~> 3.12.0)
-      rspec-mocks (~> 3.12.0)
-    rspec-core (3.12.1)
-      rspec-support (~> 3.12.0)
-    rspec-expectations (3.12.2)
+    psych (5.2.3)
+      date
+      stringio
+    racc (1.8.1)
+    rainbow (3.1.1)
+    rake (13.2.1)
+    rdoc (6.11.0)
+      psych (>= 4.0.0)
+    regexp_parser (2.10.0)
+    rexml (3.4.0)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-block_is_expected (1.0.6)
+    rspec-core (3.13.2)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-mocks (3.12.4)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.2)
+    rubocop (1.70.0)
+      json (~> 2.3)
+      language_server-protocol (>= 3.17.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.36.2, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.38.0)
+      parser (>= 3.3.1.0)
+    rubocop-gradual (0.3.6)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-support (3.12.0)
+      diffy (~> 3.0)
+      parallel (~> 1.10)
+      rainbow (>= 2.2.2, < 4.0)
+      rubocop (~> 1.0)
+    rubocop-lts (18.2.1)
+      rubocop-ruby2_7 (>= 2.0.4, < 3)
+      standard-rubocop-lts (>= 1.0.3, < 3)
+      version_gem (>= 1.1.2, < 3)
+    rubocop-md (1.2.4)
+      rubocop (>= 1.45)
+    rubocop-packaging (0.5.2)
+      rubocop (>= 1.33, < 2.0)
+    rubocop-performance (1.23.1)
+      rubocop (>= 1.48.1, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
+    rubocop-rake (0.6.0)
+      rubocop (~> 1.0)
+    rubocop-rspec (3.4.0)
+      rubocop (~> 1.61)
+    rubocop-ruby2_7 (2.0.6)
+      rubocop-gradual (~> 0.3, >= 0.3.1)
+      rubocop-md (~> 1.2)
+      rubocop-rake (~> 0.6)
+      rubocop-shopify (~> 2.14)
+      rubocop-thread_safety (~> 0.5, >= 0.5.1)
+      standard-rubocop-lts (~> 1.0, >= 1.0.7)
+      version_gem (>= 1.1.3, < 3)
+    rubocop-shopify (2.15.1)
+      rubocop (~> 1.51)
+    rubocop-thread_safety (0.6.0)
+      rubocop (>= 1.48.1)
+    ruby-progressbar (1.13.0)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-cobertura (2.1.0)
+      rexml
+      simplecov (~> 0.19)
+    simplecov-console (0.9.2)
+      ansi
+      simplecov
+      terminal-table
+    simplecov-html (0.13.1)
+    simplecov-lcov (0.8.0)
+    simplecov-rcov (0.3.7)
+      simplecov (>= 0.4.1)
+    simplecov_json_formatter (0.1.4)
+    standard (1.44.0)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.0)
+      rubocop (~> 1.70.0)
+      standard-custom (~> 1.0.0)
+      standard-performance (~> 1.6)
+    standard-custom (1.0.2)
+      lint_roller (~> 1.0)
+      rubocop (~> 1.50)
+    standard-performance (1.6.0)
+      lint_roller (~> 1.1)
+      rubocop-performance (~> 1.23.0)
+    standard-rubocop-lts (1.0.10)
+      rspec-block_is_expected (~> 1.0, >= 1.0.5)
+      standard (>= 1.35.1, < 2)
+      standard-custom (>= 1.0.2, < 2)
+      standard-performance (>= 1.3.1, < 2)
+      version_gem (>= 1.1.4, < 3)
+    stringio (3.1.2)
+    terminal-table (4.0.0)
+      unicode-display_width (>= 1.1.1, < 4)
+    thor (1.3.2)
+    unicode-display_width (3.1.4)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
+    version_gem (1.1.4)
+    yard (0.9.37)
+    yard-junk (0.0.10)
+      backports (>= 3.18)
+      ostruct
+      rainbow
+      yard
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
+  appraisal!
+  benchmark (~> 0.4)
+  bundler-audit (~> 0.9.2)
+  github-markup
+  kettle-soup-cover (~> 1.0, >= 1.0.4)
   pry (~> 0.14)
   rake (~> 13.0)
+  rdoc (~> 6.10)
+  rubocop-lts (~> 18.2, >= 18.2.1)
+  rubocop-packaging (~> 0.5, >= 0.5.2)
+  rubocop-rspec (~> 3.2)
+  standard (>= 1.35.1, != 1.42.0, != 1.41.1)
   turbo_tests!
+  yard (~> 0.9.34)
+  yard-junk (~> 0.0.10)
 
 BUNDLED WITH
-   2.4.19
+   2.6.2
diff --git a/README.md b/README.md
index f5a285a..c23b7c2 100644
--- a/README.md
+++ b/README.md
@@ -13,9 +13,9 @@
 
 </div>
 
-`turbo_tests` is a drop-in replacement for [`grosser/parallel_tests`](https://github.com/grosser/parallel_tests) with incremental summarized output. Source code of this gem is based on [Discourse](https://github.com/discourse/discourse/blob/6b9784cf8a18636bce281a7e4d18e65a0cbc6290/lib/turbo_tests.rb) and [RubyGems](https://github.com/rubygems/rubygems/tree/390335ceb351668cd433bd5bb9823dd021f82533/bundler/tool) work in this area.
+`turbo_tests` is a drop-in replacement for [grosser/parallel_tests](https://github.com/grosser/parallel_tests) with incremental summarized output. Source code of this gem is based on [Discourse](https://github.com/discourse/discourse/blob/6b9784cf8a18636bce281a7e4d18e65a0cbc6290/lib/turbo_tests.rb) and [RubyGems](https://github.com/rubygems/rubygems/tree/390335ceb351668cd433bd5bb9823dd021f82533/bundler/tool) work in this area.
 
-Incremental summarized output [doesn't fit vision of `parallel_tests` author](https://github.com/grosser/parallel_tests/issues/708) and [RSpec doesn't support built-in parallel testing yet](https://github.com/rspec/rspec-rails/issues/2104#issuecomment-658474900). This gem will not be useful once one of the issues above will be implemented.
+Incremental summarized output doesn't [fit vision](https://github.com/grosser/parallel_tests/issues/708) of `parallel_tests` author and [RSpec doesn't support built-in parallel testing yet](https://github.com/rspec/rspec-rails/issues/2104#issuecomment-658474900). This gem will not be useful once one of the issues above will be implemented.
 
 ## Why incremental output?
 
@@ -55,7 +55,7 @@ Finished in 2 minute 25.15 seconds (files took 0 seconds to load)
 Add this line to your application's `Gemfile`:
 
 ```ruby
-gem 'turbo_tests'
+gem "turbo_tests"
 ```
 
 And then execute:
@@ -70,6 +70,14 @@ Or install it yourself as:
 $ gem install turbo_tests
 ```
 
+## Setup
+
+Create test databases
+
+```bash
+$ bundle exec turbo_tests --create
+```
+
 ## Usage
 
 Execute tests:
@@ -97,6 +105,20 @@ Options:
     -v, --verbose                    More output
         --fail-fast=[N]
         --seed SEED                  Seed for rspec
+        --create                     Create test databases
+        --print_failed_group         Prints group that had failures in it
+```
+
+To pass any options supported by paralell_tests, use `--`:
+
+```bash
+bundle exec turbo_tests -n 4 -- --only-group 1 --pattern spec/system
+```
+
+`turbo_tests` supports custom formatter such as Fuubar, but you might need to require it:
+
+```bash
+bundle exec turbo_tests -r fuubar -f Fuubar spec/whatever
 ```
 
 ## Development
@@ -105,6 +127,22 @@ After checking out the repo, run `bin/setup` to install dependencies. Then, run
 
 To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
 
+### Appraisals
+
+From time to time the appraisal gemfiles in `gemfiles/` will need to be updated.
+They are created and updated with the command:
+
+```shell
+BUNDLE_GEMFILE=Appraisal.root.gemfile bundle install
+BUNDLE_GEMFILE=Appraisal.root.gemfile bundle exec appraisal update
+```
+
+NOTE: Once `eval_gemfile` support is [merged into appraisal](https://github.com/thoughtbot/appraisal/pull/248) the above commands will be simplified to:
+
+```shell
+BUNDLE_GEMFILE=Appraisal.root.gemfile appraisal update
+```
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/serpapi/turbo_tests. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/serpapi/turbo_tests/blob/master/CODE_OF_CONDUCT.md).
diff --git a/Rakefile b/Rakefile
index dbd59ee..c656deb 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,7 +1,61 @@
-require "bundler/setup"
+# frozen_string_literal: true
+
 require "bundler/gem_tasks"
-require "rspec/core/rake_task"
 
-RSpec::Core::RakeTask.new(:spec)
+begin
+  require "rspec/core/rake_task"
+
+  RSpec::Core::RakeTask.new(:spec)
+rescue LoadError
+  task(:spec) do
+    warn("RSpec is disabled")
+  end
+end
+
+desc "alias test task to spec"
+task test: :spec
+
+begin
+  require "reek/rake/task"
+  Reek::Rake::Task.new do |t|
+    t.fail_on_error = true
+    t.verbose = false
+    t.source_files = "{spec,spec_ignored,spec_orms,lib}/**/*.rb"
+  end
+rescue LoadError
+  task(:reek) do
+    warn("reek is disabled")
+  end
+end
+
+begin
+  require "yard-junk/rake"
+
+  YardJunk::Rake.define_task
+rescue LoadError
+  task("yard:junk") do
+    warn("yard:junk is disabled")
+  end
+end
+
+begin
+  require "yard"
+
+  YARD::Rake::YardocTask.new(:yard)
+rescue LoadError
+  task(:yard) do
+    warn("yard is disabled")
+  end
+end
+
+begin
+  require "rubocop/lts"
+  Rubocop::Lts.install_tasks
+rescue LoadError
+  task(:rubocop_gradual) do
+    warn("RuboCop (Gradual) is disabled")
+  end
+end
 
-task default: :spec
+# These tests do not require any services to be running, so this is what we run as default
+task default: %i[spec rubocop_gradual:autocorrect yard yard:junk]
diff --git a/bin/turbo_tests b/bin/turbo_tests
index b67291c..91d4f9d 100755
--- a/bin/turbo_tests
+++ b/bin/turbo_tests
@@ -3,7 +3,7 @@
 # frozen_string_literal: true
 
 # Enable local usage from cloned repo
-root = File.expand_path("../..", __FILE__)
+root = File.expand_path("..", __dir__)
 $LOAD_PATH << "#{root}/lib" if File.exist?("#{root}/Gemfile")
 
 require "turbo_tests"
diff --git a/fixtures/rspec/errors_outside_of_examples_spec.rb b/fixtures/rspec/errors_outside_of_examples_spec.rb
index 48738ea..9e23f50 100644
--- a/fixtures/rspec/errors_outside_of_examples_spec.rb
+++ b/fixtures/rspec/errors_outside_of_examples_spec.rb
@@ -1,5 +1,5 @@
-RSpec.describe "Fixture of spec file with errors outside of examples" do
-  it("passes") { expect(2 * 2).to eql(4) }
+RSpec.describe("Fixture of spec file with errors outside of examples") do
+  it("passes") { expect(2 * 2).to(eql(4)) }
 
   1 / 0
 end
diff --git a/fixtures/rspec/failing_spec.rb b/fixtures/rspec/failing_spec.rb
index 73a8240..4539b59 100644
--- a/fixtures/rspec/failing_spec.rb
+++ b/fixtures/rspec/failing_spec.rb
@@ -1,5 +1,5 @@
-RSpec.describe "Failing example group" do
-  after(:each) do |example|
+RSpec.describe("Failing example group") do
+  after do |example|
     example.metadata[:extra_failure_lines] ||= []
 
     lines = example.metadata[:extra_failure_lines]
@@ -8,6 +8,6 @@
   end
 
   it "fails" do
-    expect(2).to eq(3)
+    expect(2).to(eq(3))
   end
 end
diff --git a/fixtures/rspec/no_method_error_spec.rb b/fixtures/rspec/no_method_error_spec.rb
index c8c9689..86bdbbb 100644
--- a/fixtures/rspec/no_method_error_spec.rb
+++ b/fixtures/rspec/no_method_error_spec.rb
@@ -1,3 +1,3 @@
-RSpec.describe "NoMethodError spec" do
-  it("fails") { expect(nil[:key]).to eql("value") }
-end
\ No newline at end of file
+RSpec.describe("NoMethodError spec") do
+  it("fails") { expect(nil[:key]).to(eql("value")) }
+end
diff --git a/fixtures/rspec/pending_exceptions_spec.rb b/fixtures/rspec/pending_exceptions_spec.rb
index 737005f..a825dc6 100644
--- a/fixtures/rspec/pending_exceptions_spec.rb
+++ b/fixtures/rspec/pending_exceptions_spec.rb
@@ -1,15 +1,15 @@
-RSpec.describe "Fixture of spec file with pending failed examples" do
+RSpec.describe("Fixture of spec file with pending failed examples") do
   it "is implemented but skipped with 'pending'" do
     pending("TODO: skipped with 'pending'")
 
-    expect(2).to eq(3)
+    expect(2).to(eq(3))
   end
 
   it "is implemented but skipped with 'skip'", skip: "TODO: skipped with 'skip'" do
-    expect(100).to eq(500)
+    expect(100).to(eq(500))
   end
 
   xit "is implemented but skipped with 'xit'" do
-    expect(1).to eq(42)
+    expect(1).to(eq(42))
   end
 end
diff --git a/gemfiles/audit.gemfile b/gemfiles/audit.gemfile
new file mode 100644
index 0000000..b93d318
--- /dev/null
+++ b/gemfiles/audit.gemfile
@@ -0,0 +1,10 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
+
+eval_gemfile("modular/audit.gemfile")
diff --git a/gemfiles/audit.gemfile.lock b/gemfiles/audit.gemfile.lock
new file mode 100644
index 0000000..f614ea5
--- /dev/null
+++ b/gemfiles/audit.gemfile.lock
@@ -0,0 +1,60 @@
+PATH
+  remote: ..
+  specs:
+    turbo_tests (2.2.4)
+      parallel_tests (>= 3.3.0, < 5)
+      rspec (>= 3.10)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    bundler-audit (0.9.2)
+      bundler (>= 1.2.0, < 3)
+      thor (~> 1.0)
+    coderay (1.1.3)
+    diff-lcs (1.5.1)
+    method_source (1.1.0)
+    mutex_m (0.3.0)
+    parallel (1.26.3)
+    parallel_tests (4.9.0)
+      parallel
+    pry (0.15.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    rake (13.2.1)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.2)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.2)
+    stringio (3.1.2)
+    thor (1.3.2)
+
+PLATFORMS
+  aarch64-linux-gnu
+  aarch64-linux-musl
+  arm-linux-gnu
+  arm-linux-musl
+  arm64-darwin
+  x86_64-darwin
+  x86_64-linux-gnu
+  x86_64-linux-musl
+
+DEPENDENCIES
+  bundler-audit (~> 0.9.2)
+  mutex_m (~> 0.2)
+  pry (~> 0.14)
+  rake (~> 13.0)
+  stringio (~> 3.0)
+  turbo_tests!
+
+BUNDLED WITH
+   2.6.2
diff --git a/gemfiles/coverage.gemfile b/gemfiles/coverage.gemfile
new file mode 100644
index 0000000..ec3037b
--- /dev/null
+++ b/gemfiles/coverage.gemfile
@@ -0,0 +1,10 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
+
+eval_gemfile("modular/coverage.gemfile")
diff --git a/gemfiles/coverage.gemfile.lock b/gemfiles/coverage.gemfile.lock
new file mode 100644
index 0000000..2bfc00b
--- /dev/null
+++ b/gemfiles/coverage.gemfile.lock
@@ -0,0 +1,84 @@
+PATH
+  remote: ..
+  specs:
+    turbo_tests (2.2.4)
+      parallel_tests (>= 3.3.0, < 5)
+      rspec (>= 3.10)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ansi (1.5.0)
+    coderay (1.1.3)
+    diff-lcs (1.5.1)
+    docile (1.4.1)
+    kettle-soup-cover (1.0.4)
+      simplecov (~> 0.22)
+      simplecov-cobertura (~> 2.1)
+      simplecov-console (~> 0.9, >= 0.9.1)
+      simplecov-html (~> 0.12)
+      simplecov-lcov (~> 0.8)
+      simplecov-rcov (~> 0.3, >= 0.3.3)
+      simplecov_json_formatter (~> 0.1, >= 0.1.4)
+      version_gem (~> 1.1, >= 1.1.4)
+    method_source (1.1.0)
+    mutex_m (0.3.0)
+    parallel (1.26.3)
+    parallel_tests (4.9.0)
+      parallel
+    pry (0.15.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    rake (13.2.1)
+    rexml (3.4.0)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.2)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.2)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-cobertura (2.1.0)
+      rexml
+      simplecov (~> 0.19)
+    simplecov-console (0.9.2)
+      ansi
+      simplecov
+      terminal-table
+    simplecov-html (0.13.1)
+    simplecov-lcov (0.8.0)
+    simplecov-rcov (0.3.7)
+      simplecov (>= 0.4.1)
+    simplecov_json_formatter (0.1.4)
+    stringio (3.1.2)
+    terminal-table (4.0.0)
+      unicode-display_width (>= 1.1.1, < 4)
+    unicode-display_width (3.1.4)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
+    version_gem (1.1.4)
+
+PLATFORMS
+  arm64-darwin-24
+  ruby
+
+DEPENDENCIES
+  kettle-soup-cover (~> 1.0, >= 1.0.4)
+  mutex_m (~> 0.2)
+  pry (~> 0.14)
+  rake (~> 13.0)
+  stringio (~> 3.0)
+  turbo_tests!
+
+BUNDLED WITH
+   2.6.2
diff --git a/gemfiles/jruby_head.gemfile b/gemfiles/jruby_head.gemfile
new file mode 100644
index 0000000..49b0671
--- /dev/null
+++ b/gemfiles/jruby_head.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", ">= 0.2"
+gem "stringio", ">= 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/modular/audit.gemfile b/gemfiles/modular/audit.gemfile
new file mode 100644
index 0000000..e5cc919
--- /dev/null
+++ b/gemfiles/modular/audit.gemfile
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+# Many gems are dropping support for Ruby < 3,
+#   so we only want to run our security audit in CI on Ruby 3+
+gem "bundler-audit", "~> 0.9.2"
diff --git a/gemfiles/modular/coverage.gemfile b/gemfiles/modular/coverage.gemfile
new file mode 100644
index 0000000..c7756b9
--- /dev/null
+++ b/gemfiles/modular/coverage.gemfile
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+# We run code coverage on the latest version of Ruby only.
+
+# Coverage
+gem "kettle-soup-cover", "~> 1.0", ">= 1.0.4"
diff --git a/gemfiles/modular/documentation.gemfile b/gemfiles/modular/documentation.gemfile
new file mode 100644
index 0000000..c985345
--- /dev/null
+++ b/gemfiles/modular/documentation.gemfile
@@ -0,0 +1,5 @@
+### Documentation
+gem "yard", "~> 0.9.34", require: false
+gem "yard-junk", "~> 0.0.10"
+gem "github-markup"
+gem "rdoc", "~> 6.10"
diff --git a/gemfiles/modular/style.gemfile b/gemfiles/modular/style.gemfile
new file mode 100644
index 0000000..d222e96
--- /dev/null
+++ b/gemfiles/modular/style.gemfile
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+# We run rubocop on the latest version of Ruby,
+#   but in support of the oldest supported version of Ruby
+
+gem "rubocop-lts", "~> 18.2", ">= 18.2.1" # For Ruby 2.7+
+gem "rubocop-packaging", "~> 0.5", ">= 0.5.2"
+gem "rubocop-rspec", "~> 3.2"
+gem "standard", ">= 1.35.1", "!= 1.41.1", "!= 1.42.0"
+
+# Std Lib extractions
+gem "benchmark", "~> 0.4" # Removed from Std Lib in Ruby 3.5
diff --git a/gemfiles/ruby_2_7.gemfile b/gemfiles/ruby_2_7.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_2_7.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_3_0.gemfile b/gemfiles/ruby_3_0.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_3_0.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_3_1.gemfile b/gemfiles/ruby_3_1.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_3_1.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_3_2.gemfile b/gemfiles/ruby_3_2.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_3_2.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_3_3.gemfile b/gemfiles/ruby_3_3.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_3_3.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_3_4.gemfile b/gemfiles/ruby_3_4.gemfile
new file mode 100644
index 0000000..ed1eb63
--- /dev/null
+++ b/gemfiles/ruby_3_4.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_head.gemfile b/gemfiles/ruby_head.gemfile
new file mode 100644
index 0000000..49b0671
--- /dev/null
+++ b/gemfiles/ruby_head.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", ">= 0.2"
+gem "stringio", ">= 3.0"
+
+gemspec path: "../"
diff --git a/gemfiles/style.gemfile b/gemfiles/style.gemfile
new file mode 100644
index 0000000..f75762c
--- /dev/null
+++ b/gemfiles/style.gemfile
@@ -0,0 +1,10 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", "~> 0.2"
+gem "stringio", "~> 3.0"
+
+gemspec path: "../"
+
+eval_gemfile("modular/style.gemfile")
diff --git a/gemfiles/style.gemfile.lock b/gemfiles/style.gemfile.lock
new file mode 100644
index 0000000..d4ff575
--- /dev/null
+++ b/gemfiles/style.gemfile.lock
@@ -0,0 +1,135 @@
+PATH
+  remote: ..
+  specs:
+    turbo_tests (2.2.4)
+      parallel_tests (>= 3.3.0, < 5)
+      rspec (>= 3.10)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    benchmark (0.4.0)
+    coderay (1.1.3)
+    diff-lcs (1.5.1)
+    diffy (3.4.3)
+    json (2.9.1)
+    language_server-protocol (3.17.0.4)
+    lint_roller (1.1.0)
+    method_source (1.1.0)
+    mutex_m (0.3.0)
+    parallel (1.26.3)
+    parallel_tests (4.9.0)
+      parallel
+    parser (3.3.7.0)
+      ast (~> 2.4.1)
+      racc
+    pry (0.15.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    racc (1.8.1)
+    rainbow (3.1.1)
+    rake (13.2.1)
+    regexp_parser (2.10.0)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-block_is_expected (1.0.6)
+    rspec-core (3.13.2)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.2)
+    rubocop (1.70.0)
+      json (~> 2.3)
+      language_server-protocol (>= 3.17.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.36.2, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.38.0)
+      parser (>= 3.3.1.0)
+    rubocop-gradual (0.3.6)
+      diff-lcs (>= 1.2.0, < 2.0)
+      diffy (~> 3.0)
+      parallel (~> 1.10)
+      rainbow (>= 2.2.2, < 4.0)
+      rubocop (~> 1.0)
+    rubocop-lts (18.2.1)
+      rubocop-ruby2_7 (>= 2.0.4, < 3)
+      standard-rubocop-lts (>= 1.0.3, < 3)
+      version_gem (>= 1.1.2, < 3)
+    rubocop-md (1.2.4)
+      rubocop (>= 1.45)
+    rubocop-packaging (0.5.2)
+      rubocop (>= 1.33, < 2.0)
+    rubocop-performance (1.23.1)
+      rubocop (>= 1.48.1, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
+    rubocop-rake (0.6.0)
+      rubocop (~> 1.0)
+    rubocop-rspec (3.4.0)
+      rubocop (~> 1.61)
+    rubocop-ruby2_7 (2.0.6)
+      rubocop-gradual (~> 0.3, >= 0.3.1)
+      rubocop-md (~> 1.2)
+      rubocop-rake (~> 0.6)
+      rubocop-shopify (~> 2.14)
+      rubocop-thread_safety (~> 0.5, >= 0.5.1)
+      standard-rubocop-lts (~> 1.0, >= 1.0.7)
+      version_gem (>= 1.1.3, < 3)
+    rubocop-shopify (2.15.1)
+      rubocop (~> 1.51)
+    rubocop-thread_safety (0.6.0)
+      rubocop (>= 1.48.1)
+    ruby-progressbar (1.13.0)
+    standard (1.44.0)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.0)
+      rubocop (~> 1.70.0)
+      standard-custom (~> 1.0.0)
+      standard-performance (~> 1.6)
+    standard-custom (1.0.2)
+      lint_roller (~> 1.0)
+      rubocop (~> 1.50)
+    standard-performance (1.6.0)
+      lint_roller (~> 1.1)
+      rubocop-performance (~> 1.23.0)
+    standard-rubocop-lts (1.0.10)
+      rspec-block_is_expected (~> 1.0, >= 1.0.5)
+      standard (>= 1.35.1, < 2)
+      standard-custom (>= 1.0.2, < 2)
+      standard-performance (>= 1.3.1, < 2)
+      version_gem (>= 1.1.4, < 3)
+    stringio (3.1.2)
+    unicode-display_width (3.1.4)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
+    version_gem (1.1.4)
+
+PLATFORMS
+  arm64-darwin-24
+  ruby
+
+DEPENDENCIES
+  benchmark (~> 0.4)
+  mutex_m (~> 0.2)
+  pry (~> 0.14)
+  rake (~> 13.0)
+  rubocop-lts (~> 18.2, >= 18.2.1)
+  rubocop-packaging (~> 0.5, >= 0.5.2)
+  rubocop-rspec (~> 3.2)
+  standard (>= 1.35.1, != 1.42.0, != 1.41.1)
+  stringio (~> 3.0)
+  turbo_tests!
+
+BUNDLED WITH
+   2.6.2
diff --git a/gemfiles/truffleruby_head.gemfile b/gemfiles/truffleruby_head.gemfile
new file mode 100644
index 0000000..49b0671
--- /dev/null
+++ b/gemfiles/truffleruby_head.gemfile
@@ -0,0 +1,8 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "mutex_m", ">= 0.2"
+gem "stringio", ">= 3.0"
+
+gemspec path: "../"
diff --git a/lib/turbo_tests.rb b/lib/turbo_tests.rb
index afb362b..5e2df1d 100644
--- a/lib/turbo_tests.rb
+++ b/lib/turbo_tests.rb
@@ -21,24 +21,31 @@ module TurboTests
   FakeException = Struct.new(:backtrace, :message, :cause)
   class FakeException
     def self.from_obj(obj)
-      if obj
-        klass =
-          Class.new(FakeException) {
-            define_singleton_method(:name) do
-              obj[:class_name]
-            end
-          }
+      return unless obj
 
-        klass.new(
-          obj[:backtrace],
-          obj[:message],
-          FakeException.from_obj(obj[:cause])
-        )
-      end
+      klass =
+        Class.new(FakeException) do
+          define_singleton_method(:name) do
+            obj[:class_name]
+          end
+        end
+
+      klass.new(
+        obj[:backtrace],
+        obj[:message],
+        FakeException.from_obj(obj[:cause]),
+      )
     end
   end
 
-  FakeExecutionResult = Struct.new(:example_skipped?, :pending_message, :status, :pending_fixed?, :exception, :pending_exception)
+  FakeExecutionResult = Struct.new(
+    :example_skipped?,
+    :pending_message,
+    :status,
+    :pending_fixed?,
+    :exception,
+    :pending_exception,
+  )
   class FakeExecutionResult
     def self.from_obj(obj)
       new(
@@ -47,12 +54,19 @@ def self.from_obj(obj)
         obj[:status].to_sym,
         obj[:pending_fixed?],
         FakeException.from_obj(obj[:exception]),
-        FakeException.from_obj(obj[:exception])
+        FakeException.from_obj(obj[:exception]),
       )
     end
   end
 
-  FakeExample = Struct.new(:execution_result, :location, :description, :full_description, :metadata, :location_rerun_argument)
+  FakeExample = Struct.new(
+    :execution_result,
+    :location,
+    :description,
+    :full_description,
+    :metadata,
+    :location_rerun_argument,
+  )
   class FakeExample
     def self.from_obj(obj)
       metadata = obj[:metadata]
@@ -60,7 +74,7 @@ def self.from_obj(obj)
       metadata[:shared_group_inclusion_backtrace].map! do |frame|
         RSpec::Core::SharedExampleGroupInclusionStackFrame.new(
           frame[:shared_group_name],
-          frame[:inclusion_location]
+          frame[:inclusion_location],
         )
       end
 
@@ -72,13 +86,13 @@ def self.from_obj(obj)
         obj[:description],
         obj[:full_description],
         metadata,
-        obj[:location_rerun_argument]
+        obj[:location_rerun_argument],
       )
     end
 
     def notification
       RSpec::Core::Notifications::ExampleNotification.for(
-        self
+        self,
       )
     end
   end
diff --git a/lib/turbo_tests/cli.rb b/lib/turbo_tests/cli.rb
index 6f033cc..ae6f445 100644
--- a/lib/turbo_tests/cli.rb
+++ b/lib/turbo_tests/cli.rb
@@ -17,8 +17,11 @@ def run
       verbose = false
       fail_fast = nil
       seed = nil
+      print_failed_group = false
+      create = false
+      nice = false
 
-      OptionParser.new { |opts|
+      OptionParser.new do |opts|
         opts.banner = <<~BANNER
           Run all tests in parallel, giving each process ENV['TEST_ENV_NUMBER'] ('1', '2', '3', ...).
 
@@ -40,10 +43,14 @@ def run
           requires << filename
         end
 
-        opts.on("-f", "--format FORMATTER", "Choose a formatter. Available formatters: progress (p), documentation (d). Default: progress") do |name|
+        opts.on(
+          "-f",
+          "--format FORMATTER",
+          "Choose a formatter. Available formatters: progress (p), documentation (d). Default: progress",
+        ) do |name|
           formatters << {
             name: name,
-            outputs: []
+            outputs: [],
           }
         end
 
@@ -55,7 +62,7 @@ def run
           if formatters.empty?
             formatters << {
               name: "progress",
-              outputs: []
+              outputs: [],
             }
           end
           formatters.last[:outputs] << filename
@@ -72,45 +79,65 @@ def run
         opts.on("--fail-fast=[N]") do |n|
           n = begin
             Integer(n)
-          rescue
+          rescue StandardError
             nil
           end
-          fail_fast = n.nil? || n < 1 ? 1 : n
+          fail_fast = (n.nil? || n < 1) ? 1 : n
         end
 
         opts.on("--seed SEED", "Seed for rspec") do |s|
           seed = s
         end
-      }.parse!(@argv)
+
+        opts.on("--create", "Create databases") do
+          create = true
+        end
+
+        opts.on("--print_failed_group", "Prints group that had failures in it") do
+          print_failed_group = true
+        end
+
+        opts.on("--nice", "execute test commands with low priority") do
+          nice = true
+        end
+      end.parse!(@argv)
+
+      if create
+        return TurboTests::Runner.create(count)
+      end
 
       requires.each { |f| require(f) }
 
       if formatters.empty?
         formatters << {
           name: "progress",
-          outputs: []
+          outputs: [],
         }
       end
 
       formatters.each do |formatter|
-        if formatter[:outputs].empty?
-          formatter[:outputs] << "-"
-        end
+        formatter[:outputs] << "-" if formatter[:outputs].empty?
       end
 
+      parallel_options = ParallelTests::CLI.new.send(:parse_options!, @argv.unshift("--type", "rspec"))
+      files = parallel_options.fetch(:files, ["spec"])
+
       exitstatus = TurboTests::Runner.run(
         formatters: formatters,
         tags: tags,
-        files: @argv.empty? ? ["spec"] : @argv,
+        files: files,
         runtime_log: runtime_log,
         verbose: verbose,
         fail_fast: fail_fast,
         count: count,
-        seed: seed
+        seed: seed,
+        nice: nice,
+        print_failed_group: print_failed_group,
+        parallel_options: parallel_options,
       )
 
       # From https://github.com/serpapi/turbo_tests/pull/20/
-      exit exitstatus
+      exit(exitstatus)
     end
   end
 end
diff --git a/lib/turbo_tests/json_rows_formatter.rb b/lib/turbo_tests/json_rows_formatter.rb
index d0244ca..276d945 100644
--- a/lib/turbo_tests/json_rows_formatter.rb
+++ b/lib/turbo_tests/json_rows_formatter.rb
@@ -30,7 +30,7 @@ class JsonRowsFormatter
       :example_group_started,
       :example_group_finished,
       :message,
-      :seed
+      :seed,
     )
 
     attr_reader :output
@@ -42,76 +42,76 @@ def initialize(output)
     def start(notification)
       output_row(
         type: :load_summary,
-        summary: load_summary_to_json(notification)
+        summary: load_summary_to_json(notification),
       )
     end
 
     def example_group_started(notification)
       output_row(
         type: :group_started,
-        group: group_to_json(notification)
+        group: group_to_json(notification),
       )
     end
 
     def example_group_finished(notification)
       output_row(
         type: :group_finished,
-        group: group_to_json(notification)
+        group: group_to_json(notification),
       )
     end
 
     def example_passed(notification)
       output_row(
         type: :example_passed,
-        example: example_to_json(notification.example)
+        example: example_to_json(notification.example),
       )
     end
 
     def example_pending(notification)
       output_row(
         type: :example_pending,
-        example: example_to_json(notification.example)
+        example: example_to_json(notification.example),
       )
     end
 
     def example_failed(notification)
       output_row(
         type: :example_failed,
-        example: example_to_json(notification.example)
+        example: example_to_json(notification.example),
       )
     end
 
     def seed(notification)
       output_row(
         type: :seed,
-        seed: notification.seed
+        seed: notification.seed,
       )
     end
 
-    def close(notification)
+    def close(_notification)
       output_row(
-        type: :close
+        type: :close,
       )
     end
 
     def message(notification)
       output_row(
         type: :message,
-        message: notification.message
+        message: notification.message,
       )
     end
 
     private
 
     def exception_to_json(exception)
-      if exception
-        {
-          class_name: exception.class.name.to_s,
-          backtrace: exception.backtrace,
-          message: exception.message,
-          cause: exception_to_json(exception.cause)
-        }
-      end
+      return unless exception
+
+      {
+        class_name: exception.class.name.to_s,
+        backtrace: exception.backtrace,
+        message: exception.message,
+        cause: exception_to_json(exception.cause),
+      }
     end
 
     def execution_result_to_json(result)
@@ -120,14 +120,14 @@ def execution_result_to_json(result)
         pending_message: result.pending_message,
         status: result.status,
         pending_fixed?: result.pending_fixed?,
-        exception: exception_to_json(result.exception || result.pending_exception)
+        exception: exception_to_json(result.exception || result.pending_exception),
       }
     end
 
     def stack_frame_to_json(frame)
       {
         shared_group_name: frame.shared_group_name,
-        inclusion_location: frame.inclusion_location
+        inclusion_location: frame.inclusion_location,
       }
     end
 
@@ -158,8 +158,8 @@ def load_summary_to_json(notification)
     def group_to_json(notification)
       {
         group: {
-          description: notification.group.description
-        }
+          description: notification.group.description,
+        },
       }
     end
 
diff --git a/lib/turbo_tests/reporter.rb b/lib/turbo_tests/reporter.rb
index 417f06a..acd2f76 100644
--- a/lib/turbo_tests/reporter.rb
+++ b/lib/turbo_tests/reporter.rb
@@ -3,27 +3,27 @@
 module TurboTests
   class Reporter
     attr_writer :load_time
+    attr_reader :pending_examples, :failed_examples
 
-    def self.from_config(formatter_config, start_time, seed, seed_used)
-      reporter = new(start_time, seed, seed_used)
+    class << self
+      def from_config(formatter_config, start_time, seed, seed_used, files, parallel_options)
+        reporter = new(start_time, seed, seed_used, files, parallel_options)
 
-      formatter_config.each do |config|
-        name, outputs = config.values_at(:name, :outputs)
+        formatter_config.each do |config|
+          name, outputs = config.values_at(:name, :outputs)
 
-        outputs.map! do |filename|
-          filename == "-" ? $stdout : File.open(filename, "w")
+          outputs.map! do |filename|
+            (filename == "-") ? $stdout : File.open(filename, "w")
+          end
+
+          reporter.add(name, outputs)
         end
 
-        reporter.add(name, outputs)
+        reporter
       end
-
-      reporter
     end
 
-    attr_reader :pending_examples
-    attr_reader :failed_examples
-
-    def initialize(start_time, seed, seed_used)
+    def initialize(start_time, seed, seed_used, files, parallel_options)
       @formatters = []
       @pending_examples = []
       @failed_examples = []
@@ -34,6 +34,8 @@ def initialize(start_time, seed, seed_used)
       @seed_used = seed_used
       @load_time = 0
       @errors_outside_of_examples_count = 0
+      @files = files
+      @parallel_options = parallel_options
     end
 
     def add(name, outputs)
@@ -63,7 +65,7 @@ def report(example_groups)
       end
     end
 
-    def start(example_groups, time=RSpec::Core::Time.now)
+    def start(example_groups, time = RSpec::Core::Time.now)
       @start = time
       @load_time = (@start - @start_time).to_f
 
@@ -71,7 +73,10 @@ def start(example_groups, time=RSpec::Core::Time.now)
       expected_example_count = example_groups.flatten(1).count
 
       delegate_to_formatters(:seed, RSpec::Core::Notifications::SeedNotification.new(@seed, @seed_used))
-      delegate_to_formatters(:start, RSpec::Core::Notifications::StartNotification.new(expected_example_count, @load_time))
+      delegate_to_formatters(
+        :start,
+        RSpec::Core::Notifications::StartNotification.new(expected_example_count, @load_time),
+      )
     end
 
     def report_number_of_tests(groups)
@@ -79,7 +84,7 @@ def report_number_of_tests(groups)
 
       num_processes = groups.size
       num_tests = groups.map(&:size).sum
-      tests_per_process = (num_processes == 0 ? 0 : num_tests.to_f / num_processes).round
+      tests_per_process = ((num_processes == 0) ? 0 : num_tests.to_f / num_processes).round
 
       puts "#{num_processes} processes for #{num_tests} #{name}s, ~ #{tests_per_process} #{name}s per process"
     end
@@ -119,40 +124,48 @@ def message(message)
 
     def error_outside_of_examples(error_message)
       @errors_outside_of_examples_count += 1
-      message error_message
+      message(error_message)
     end
 
     def finish
       end_time = RSpec::Core::Time.now
 
       @duration = end_time - @start_time
-      delegate_to_formatters :stop, RSpec::Core::Notifications::ExamplesNotification.new(self)
+      delegate_to_formatters(:stop, RSpec::Core::Notifications::ExamplesNotification.new(self))
 
-      delegate_to_formatters :start_dump, RSpec::Core::Notifications::NullNotification
-      delegate_to_formatters(:dump_pending,
+      delegate_to_formatters(:start_dump, RSpec::Core::Notifications::NullNotification)
+      delegate_to_formatters(
+        :dump_pending,
         RSpec::Core::Notifications::ExamplesNotification.new(
-          self
-        ))
-      delegate_to_formatters(:dump_failures,
+          self,
+        ),
+      )
+      delegate_to_formatters(
+        :dump_failures,
         RSpec::Core::Notifications::ExamplesNotification.new(
-          self
-        ))
-      delegate_to_formatters(:dump_summary,
+          self,
+        ),
+      )
+      delegate_to_formatters(
+        :dump_summary,
         RSpec::Core::Notifications::SummaryNotification.new(
           end_time - @start_time,
           @all_examples,
           @failed_examples,
           @pending_examples,
           @load_time,
-          @errors_outside_of_examples_count
-        ))
-      delegate_to_formatters(:seed,
+          @errors_outside_of_examples_count,
+        ),
+      )
+      delegate_to_formatters(
+        :seed,
         RSpec::Core::Notifications::SeedNotification.new(
           @seed,
           @seed_used,
-        ))
+        ),
+      )
     ensure
-      delegate_to_formatters :close, RSpec::Core::Notifications::NullNotification
+      delegate_to_formatters(:close, RSpec::Core::Notifications::NullNotification)
     end
 
     protected
diff --git a/lib/turbo_tests/runner.rb b/lib/turbo_tests/runner.rb
index 9db297d..d428512 100644
--- a/lib/turbo_tests/runner.rb
+++ b/lib/turbo_tests/runner.rb
@@ -9,27 +9,49 @@ module TurboTests
   class Runner
     using CoreExtensions
 
+    def self.create(count)
+      # We are unable to load parallel tests' tasks in the normal way (top of file)
+      # because it requires that the Rails.application instance already be configured
+      require "parallel_tests/tasks"
+
+      ENV["PARALLEL_TEST_FIRST_IS_1"] = "true"
+      command = ["bundle", "exec", "rake", "db:create", "RAILS_ENV=#{ParallelTests::Tasks.rails_env}"]
+      args = {count: count.to_s}
+      ParallelTests::Tasks.run_in_parallel(command, args)
+    end
+
     def self.run(opts = {})
       files = opts[:files]
       formatters = opts[:formatters]
       tags = opts[:tags]
+      parallel_options = opts[:parallel_options] || {}
 
       start_time = opts.fetch(:start_time) { RSpec::Core::Time.now }
       runtime_log = opts.fetch(:runtime_log, nil)
       verbose = opts.fetch(:verbose, false)
       fail_fast = opts.fetch(:fail_fast, nil)
       count = opts.fetch(:count, nil)
-      seed = opts.fetch(:seed)
+      seed = opts.fetch(:seed, nil)
       seed_used = !seed.nil?
+      print_failed_group = opts.fetch(:print_failed_group, false)
+      nice = opts.fetch(:nice, false)
+
+      use_runtime_info = files == ["spec"]
 
-      if verbose
-        warn "VERBOSE"
+      if use_runtime_info
+        parallel_options[:runtime_log] = runtime_log
+      else
+        parallel_options[:group_by] = :filesize
       end
 
-      reporter = Reporter.from_config(formatters, start_time, seed, seed_used)
+      warn("VERBOSE") if verbose
+
+      reporter = Reporter.from_config(formatters, start_time, seed, seed_used, files, parallel_options)
 
       new(
         reporter: reporter,
+        formatters: formatters,
+        start_time: start_time,
         files: files,
         tags: tags,
         runtime_log: runtime_log,
@@ -38,85 +60,102 @@ def self.run(opts = {})
         count: count,
         seed: seed,
         seed_used: seed_used,
+        print_failed_group: print_failed_group,
+        use_runtime_info: use_runtime_info,
+        parallel_options: parallel_options,
+        nice: nice,
       ).run
     end
 
-    def initialize(opts)
+    def initialize(**opts)
+      @formatters = opts[:formatters]
       @reporter = opts[:reporter]
       @files = opts[:files]
       @tags = opts[:tags]
-      @runtime_log = opts[:runtime_log] || "tmp/turbo_rspec_runtime.log"
       @verbose = opts[:verbose]
       @fail_fast = opts[:fail_fast]
+      @start_time = opts[:start_time]
       @count = opts[:count]
       @seed = opts[:seed]
       @seed_used = opts[:seed_used]
+      @nice = opts[:nice]
+      @use_runtime_info = opts[:use_runtime_info]
 
       @load_time = 0
       @load_count = 0
       @failure_count = 0
 
+      # Supports runtime_log as a top level option,
+      #   but also nested inside parallel_options
+      @runtime_log = opts[:runtime_log] || "tmp/turbo_rspec_runtime.log"
+      @parallel_options = opts.fetch(:parallel_options, {})
+      @parallel_options[:runtime_log] ||= @runtime_log
+      @record_runtime = @parallel_options[:group_by] == :runtime
+
       @messages = Thread::Queue.new
       @threads = []
+      @wait_threads = []
       @error = false
+      @print_failed_group = opts[:print_failed_group]
     end
 
     def run
       @num_processes = [
         ParallelTests.determine_number_of_processes(@count),
-        ParallelTests::RSpec::Runner.tests_with_size(@files, {}).size
+        ParallelTests::RSpec::Runner.tests_with_size(@files, {}).size,
       ].min
 
-      use_runtime_info = @files == ["spec"]
-
-      group_opts = {}
-
-      if use_runtime_info
-        group_opts[:runtime_log] = @runtime_log
-      else
-        group_opts[:group_by] = :filesize
-      end
-
       tests_in_groups =
         ParallelTests::RSpec::Runner.tests_in_groups(
           @files,
           @num_processes,
-          **group_opts
+          **@parallel_options,
         )
 
-      setup_tmp_dir
-
       subprocess_opts = {
-        record_runtime: use_runtime_info,
+        record_runtime: @record_runtime,
       }
 
-      @reporter.report(tests_in_groups) do |reporter|
-        wait_threads = tests_in_groups.map.with_index do |tests, process_id|
+      @reporter.report(tests_in_groups) do |_reporter|
+        old_signal = Signal.trap(:INT) { handle_interrupt }
+
+        @wait_threads = tests_in_groups.map.with_index do |tests, process_id|
           start_regular_subprocess(tests, process_id + 1, **subprocess_opts)
-        end
+        end.compact
+        @interrupt_handled = false
 
         handle_messages
 
         @threads.each(&:join)
 
-        if @reporter.failed_examples.empty? && wait_threads.map(&:value).all?(&:success?)
+        report_failed_group(tests_in_groups) if @print_failed_group
+
+        Signal.trap(:INT, old_signal)
+
+        if @reporter.failed_examples.empty? && @wait_threads.map(&:value).all?(&:success?)
           0
         else
           # From https://github.com/serpapi/turbo_tests/pull/20/
-          wait_threads.map { |thread| thread.value.exitstatus }.max
+          @wait_threads.map { |thread| thread.value.exitstatus }.max
         end
       end
     end
 
     private
 
-    def setup_tmp_dir
-      begin
-        FileUtils.rm_r("tmp/test-pipes")
-      rescue Errno::ENOENT
+    def handle_interrupt
+      if @interrupt_handled
+        Kernel.exit
+      else
+        puts "\nShutting down subprocesses..."
+        @wait_threads.each do |wait_thr|
+          child_pid = wait_thr.pid
+          pgid = Process.respond_to?(:getpgid) ? Process.getpgid(child_pid) : 0
+          Process.kill(:INT, child_pid) if Process.pid != pgid
+        rescue Errno::ESRCH, Errno::ENOENT
+        end
+        @interrupt_handled = true
       end
-
-      FileUtils.mkdir_p("tmp/test-pipes/")
     end
 
     def start_regular_subprocess(tests, process_id, **opts)
@@ -125,7 +164,7 @@ def start_regular_subprocess(tests, process_id, **opts)
         @tags.map { |tag| "--tag=#{tag}" },
         tests,
         process_id,
-        **opts
+        **opts,
       )
     end
 
@@ -135,22 +174,29 @@ def start_subprocess(env, extra_args, tests, process_id, record_runtime:)
           type: "exit",
           process_id: process_id,
         }
+
+        nil
       else
         env["RSPEC_FORMATTER_OUTPUT_ID"] = SecureRandom.uuid
         env["RUBYOPT"] = ["-I#{File.expand_path("..", __dir__)}", ENV["RUBYOPT"]].compact.join(" ")
         env["RSPEC_SILENCE_FILTER_ANNOUNCEMENTS"] = "1"
 
-        if ENV["BUNDLE_BIN_PATH"]
-          command_name = [ENV["BUNDLE_BIN_PATH"], "exec", "rspec"]
-        else
-          command_name = "rspec"
-        end
+        command_name =
+          if ENV["RSPEC_EXECUTABLE"]
+            ENV["RSPEC_EXECUTABLE"].split
+          elsif ENV["BUNDLE_BIN_PATH"]
+            [ENV["BUNDLE_BIN_PATH"], "exec", "rspec"]
+          else
+            "rspec"
+          end
 
         record_runtime_options =
           if record_runtime
             [
-              "--format", "ParallelTests::RSpec::RuntimeLogger",
-              "--out", @runtime_log,
+              "--format",
+              "ParallelTests::RSpec::RuntimeLogger",
+              "--out",
+              @runtime_log,
             ]
           else
             []
@@ -164,14 +210,19 @@ def start_subprocess(env, extra_args, tests, process_id, record_runtime:)
           []
         end
 
+        spec_opts = ParallelTests::RSpec::Runner.send(:spec_opts)
+
         command = [
           *command_name,
           *extra_args,
           *seed_option,
-          "--format", "TurboTests::JsonRowsFormatter",
+          "--format",
+          "TurboTests::JsonRowsFormatter",
           *record_runtime_options,
+          *spec_opts,
           *tests,
         ]
+        command.unshift("nice") if @nice
 
         if @verbose
           command_str = [
@@ -179,7 +230,7 @@ def start_subprocess(env, extra_args, tests, process_id, record_runtime:)
             command.join(" "),
           ].select { |x| x.size > 0 }.join(" ")
 
-          warn "Process #{process_id}: #{command_str}"
+          warn("Process #{process_id}: #{command_str}")
         end
 
         stdin, stdout, stderr, wait_thr = Open3.popen3(env, *command)
@@ -190,26 +241,25 @@ def start_subprocess(env, extra_args, tests, process_id, record_runtime:)
             stdout.each_line do |line|
               result = line.split(env["RSPEC_FORMATTER_OUTPUT_ID"])
 
-              output = result.shift
-              print(output) unless output.empty?
+              initial = result.shift
+              print(initial) unless initial.empty?
 
               message = result.shift
               next unless message
 
               message = JSON.parse(message, symbolize_names: true)
+
               message[:process_id] = process_id
               @messages << message
             end
 
-            @messages << { type: "exit", process_id: process_id }
+            @messages << {type: "exit", process_id: process_id}
           end
 
         @threads << start_copy_thread(stderr, STDERR)
 
         @threads << Thread.new do
-          unless wait_thr.value.success?
-            @messages << { type: "error" }
-          end
+          @messages << {type: "error"} unless wait_thr.value.success?
         end
 
         wait_thr
@@ -272,11 +322,9 @@ def handle_messages
           nil
         when "exit"
           exited += 1
-          if exited == @num_processes
-            break
-          end
+          break if exited == @num_processes
         else
-          STDERR.puts("Unhandled message in main process: #{message}")
+          warn("Unhandled message in main process: #{message}")
         end
 
         STDOUT.flush
@@ -287,5 +335,14 @@ def handle_messages
     def fail_fast_met
       !@fail_fast.nil? && @failure_count >= @fail_fast
     end
+
+    def report_failed_group(tests_in_groups)
+      @wait_threads.map(&:value).each_with_index do |value, index|
+        next if value.success?
+
+        failing_group = tests_in_groups[index].join(" ")
+        puts "Group that failed: #{failing_group}"
+      end
+    end
   end
 end
diff --git a/lib/utils/hash_extension.rb b/lib/utils/hash_extension.rb
index c00bf6e..0b1da04 100644
--- a/lib/utils/hash_extension.rb
+++ b/lib/utils/hash_extension.rb
@@ -1,7 +1,7 @@
 module CoreExtensions
   refine Hash do
     def to_struct
-      Struct.new(*self.keys).new(*self.values.map { |value| value.is_a?(Hash) ? value.to_struct : value })
+      Struct.new(*keys).new(*values.map { |value| value.is_a?(Hash) ? value.to_struct : value })
     end
   end
-end
\ No newline at end of file
+end
diff --git a/spec/cli_spec.rb b/spec/cli_spec.rb
index 93fa132..06d74fd 100644
--- a/spec/cli_spec.rb
+++ b/spec/cli_spec.rb
@@ -1,35 +1,28 @@
 RSpec.describe TurboTests::CLI do
-  before { output }
+  subject(:output) { %x(bundle exec turbo_tests -f d #{fixture}).strip }
 
-  subject(:output) { `bundle exec turbo_tests -f d #{fixture}`.strip }
+  before { output }
 
   context "when the 'seed' parameter was used" do
-    let(:seed) { 1234 }
+    subject(:output) { %x(bundle exec turbo_tests -f d #{fixture} --seed #{seed}).strip }
 
-    subject(:output) { `bundle exec turbo_tests -f d #{fixture} --seed #{seed}`.strip }
+    let(:seed) { 1234 }
 
     context "errors outside of examples" do
-      let(:expected_start_of_output) {
-%(
+      let(:expected_start_of_output) do
+        %(
 1 processes for 1 specs, ~ 1 specs per process
 
 Randomized with seed #{seed}
 
 An error occurred while loading #{fixture}.
-\e[31mFailure/Error: \e[0m\e[1;34m1\e[0m / \e[1;34m0\e[0m\e[0m
-\e[31m\e[0m
-\e[31mZeroDivisionError:\e[0m
-\e[31m  divided by 0\e[0m
-\e[36m# #{fixture}:4:in `/'\e[0m
-\e[36m# #{fixture}:4:in `block in <top (required)>'\e[0m
-\e[36m# #{fixture}:1:in `<top (required)>'\e[0m
 ).strip
-      }
+      end
 
       let(:expected_end_of_output) do
-        "0 examples, 0 failures, 1 error occurred outside of examples\n"\
-        "\n"\
-        "Randomized with seed #{seed}"
+        "0 examples, 0 failures, 1 error occurred outside of examples\n" \
+          "\n" \
+          "Randomized with seed #{seed}"
       end
 
       let(:fixture) { "./fixtures/rspec/errors_outside_of_examples_spec.rb" }
@@ -65,20 +58,13 @@
 
   context "when 'seed' parameter was not used" do
     context "errors outside of examples" do
-      let(:expected_start_of_output) {
-%(
+      let(:expected_start_of_output) do
+        %(
 1 processes for 1 specs, ~ 1 specs per process
 
 An error occurred while loading #{fixture}.
-\e[31mFailure/Error: \e[0m\e[1;34m1\e[0m / \e[1;34m0\e[0m\e[0m
-\e[31m\e[0m
-\e[31mZeroDivisionError:\e[0m
-\e[31m  divided by 0\e[0m
-\e[36m# #{fixture}:4:in `/'\e[0m
-\e[36m# #{fixture}:4:in `block in <top (required)>'\e[0m
-\e[36m# #{fixture}:1:in `<top (required)>'\e[0m
 ).strip
-      }
+      end
 
       let(:expected_end_of_output) do
         "0 examples, 0 failures, 1 error occurred outside of examples"
@@ -94,7 +80,7 @@
       end
 
       it "exludes the seed message from the output" do
-        expect(output).to_not include("seed")
+        expect(output).not_to include("seed")
       end
     end
 
@@ -136,12 +122,12 @@
       expect($?.exitstatus).to eql(1)
 
       [
-        "undefined method `[]' for nil",
-        'it("fails") { expect(nil[:key]).to eql("value") }',
-        "# #{fixture}:2:in `block (2 levels) in <top (required)>'",
-        "1 example, 1 failure",
+        /undefined method [`']\[\]' for nil/,
+        /it\("fails"\) \{ expect\(nil\[:key\]\).to\(eql\("value"\)\) \}/,
+        /# #{Regexp.escape(fixture)}:2:in [`']block \(2 levels\) in <top \(required\)>'/,
+        /1 example, 1 failure/,
       ].each do |part|
-        expect(output).to include(part)
+        expect(output).to match(part)
       end
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 3e568ab..6bad508 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,7 @@
-require "bundler/setup"
 require "turbo_tests"
 
+require "parallel_tests/tasks"
+
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure
   config.example_status_persistence_file_path = ".rspec_status"
diff --git a/spec/turbo_tests_spec.rb b/spec/turbo_tests_spec.rb
index 0ee2784..438ccb1 100644
--- a/spec/turbo_tests_spec.rb
+++ b/spec/turbo_tests_spec.rb
@@ -1,5 +1,27 @@
 RSpec.describe TurboTests do
   it "has a version number" do
-    expect(TurboTests::VERSION).not_to be nil
+    expect(TurboTests::VERSION).not_to be_nil
+  end
+
+  describe "create" do
+    context "with nil count" do
+      it "creates databases" do
+        expect(ParallelTests::Tasks)
+          .to receive(:run_in_parallel)
+          .with(["bundle", "exec", "rake", "db:create", "RAILS_ENV=test"], {count: ""})
+
+        TurboTests::Runner.create(nil)
+      end
+    end
+
+    context "with count" do
+      it "creates databases" do
+        expect(ParallelTests::Tasks)
+          .to receive(:run_in_parallel)
+          .with(["bundle", "exec", "rake", "db:create", "RAILS_ENV=test"], {count: "4"})
+
+        TurboTests::Runner.create(4)
+      end
+    end
   end
 end
diff --git a/turbo_tests.gemspec b/turbo_tests.gemspec
index 52064e1..1556a89 100644
--- a/turbo_tests.gemspec
+++ b/turbo_tests.gemspec
@@ -4,7 +4,6 @@ Gem::Specification.new do |spec|
   spec.name = "turbo_tests"
   spec.version = TurboTests::VERSION
   spec.platform = Gem::Platform::RUBY
-  spec.date = Time.now.strftime('%Y-%m-%d')
 
   spec.summary = "`turbo_tests` is a drop-in replacement for `grosser/parallel_tests` with incremental summarized output. Source code of `turbo_test` gem is based on Discourse and Rubygems work in this area (see README file of the source repository)."
   spec.homepage = "https://github.com/serpapi/turbo_tests"
@@ -19,15 +18,16 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = ">= 2.7"
 
-  spec.add_dependency "rspec", ">= 3.10"
-  spec.add_dependency "parallel_tests", ">= 3.3.0", "< 5"
+  spec.add_dependency("parallel_tests", ">= 3.3.0", "< 5")
+  spec.add_dependency("rspec", ">= 3.10")
 
-  spec.add_development_dependency "pry", "~> 0.14"
+  spec.add_development_dependency("pry", "~> 0.14")
+  spec.add_development_dependency("rake", "~> 13.0")
 
   # Specify which files should be added to the gem when it is released.
   # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
-  spec.files = Dir.chdir(File.expand_path("..", __FILE__)) do
-    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  spec.files = Dir.chdir(File.expand_path(__dir__)) do
+    %x(git ls-files -z).split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   end
 
   spec.executables = ["turbo_tests"]