diff --git a/.Rbuildignore b/.Rbuildignore
index b8a674fa..bfce554a 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -16,3 +16,4 @@
 ^tools/dist$
 ^compile_commands\.json$
 ^\.cache$
+^docker-compose\.yml$
diff --git a/docker-compose.yml b/docker-compose.yml
new file mode 100644
index 00000000..82df6ffc
--- /dev/null
+++ b/docker-compose.yml
@@ -0,0 +1,8 @@
+services:
+  ubuntu-focal:
+    build:
+      context: .
+      dockerfile: tools/docker/ubuntu-focal.dockerfile
+    volumes:
+      - .:/s2
+    command: bash
diff --git a/tests/testthat/test-s2-cell.R b/tests/testthat/test-s2-cell.R
index 27a938df..fb02b7a0 100644
--- a/tests/testthat/test-s2-cell.R
+++ b/tests/testthat/test-s2-cell.R
@@ -11,6 +11,8 @@ test_that("s2_cell class works", {
 })
 
 test_that("s2_cell bit64::integer64 support works", {
+  skip_if_not_installed("bit64")
+
   cells <- c(as_s2_cell(NA_character_), s2_cell_sentinel())
   int64s <- bit64::as.integer64(cells)
   expect_identical(int64s, bit64::as.integer64(c(NA, -1)))
diff --git a/tools/docker/ubuntu-focal.dockerfile b/tools/docker/ubuntu-focal.dockerfile
new file mode 100644
index 00000000..37b5953b
--- /dev/null
+++ b/tools/docker/ubuntu-focal.dockerfile
@@ -0,0 +1,12 @@
+
+FROM ubuntu:focal
+
+ENV TZ=UTC
+RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
+    r-base cmake \
+    libudunits2-dev libgdal-dev libgeos-dev libproj-dev \
+    libcurl4-openssl-dev libssl-dev
+
+# Make sure we can use all cores to install things
+RUN mkdir ~/.R && echo "MAKEFLAGS = -j$(nproc)" > ~/.R/Makevars
+RUN R -e 'install.packages(c("wk", "Rcpp", "testthat"), repos = "https://cloud.r-project.org")'