Merge pull request #2 from san99tiago/develop

Include UnitTests for the Lambda Function

important_commands.sh

@@ -32,6 +32,8 @@ pip install aws-cdk-lib
 
 # Configure AWS credentials (follow steps)
 aws configure
+# --> Alternative 1: Environment variables added to terminal session
+# --> Alternative 2: AWS Cloud9 with the right permissions
 
 # Bootstrap CDK (provision initial resources to work with CDK.. S3, roles, etc)
 #! Change "ACCOUNT-NUMBER" and "REGION" to your needed values 
@@ -56,13 +58,19 @@ pip install -r requirements.txt || pip3 install -r requirements.txt
 # PART 3: Main CDK and Python commands (most used)
 ################################################################################
 
-cdk bootstrap
-source .venv/bin/activate || echo "Make sure that virtual env exists"
+# Activate Python virtual environment and check dependencies installed
+# --> On the root of the repository (same context as this file), run:
+source ./cdk/.venv/bin/activate || echo "Make sure that virtual env exists"
+pip install -r ./cdk/requirements.txt
+pip install -r ./lambda/requirements.txt
+pip install -r ./lambda/requirements-dev.txt
 
-# Test Lambda Python Stack
+# Test Lambda Python Stack (optional)
+# --> On the root of the repository (same context as this file), run:
 python -m pytest
 
 # CDK commands
+# --> On the "./cdk" folder, run:
 cdk bootstrap
 cdk synthesize
 cdk diff

lambda/requirements-dev.txt

@@ -0,0 +1,2 @@
+pytest==6.2.5
+moto==4.1.7

lambda/src/lambda_function.py

@@ -38,7 +38,7 @@ def process_messages(event: SQSEvent):
         # Note: if input does not contain "Message" key, this will raise an error
         message = json.loads(payload)["Message"]
         logger.info("Message: {}".format(message))
-
+    return True
 
 @logger.inject_lambda_context(log_event=True)
 @event_source(data_class=SQSEvent)
@@ -47,7 +47,8 @@ def handler(event: SQSEvent, context: LambdaContext) -> str:
     logger.debug("Starting messages processing")
     tracer.put_metadata(key="details", value="messages processing handler")
     try:
-        process_messages(event)
+        result = process_messages(event)
+        logger.debug(result)
     except Exception as e:
         logger.exception("Error processing the messages")
         raise RuntimeError("Processing failed for the input messages") from e

lambda/tests/test_event_01_good_single.json

@@ -0,0 +1,21 @@
+{
+  "Records": [
+    {
+      "messageId": "4332b17c-b7cd-4aef-8dba-7cb7240e3d0e",
+      "receiptHandle": "AWEBZGy/Ajve1xtBoqIJhPmO0ANH9FWhcpjt7xevdsSw5+BK0OIljV8Jq/6SNgQ9boZKcTdGkK2aaiSo9iCAgsnSyUJ3u3FenB5rOnlOTf3ctMHHEJ4tGrwSR6lx8be8/CggdbtuCxjzZsPU2IUEIo4URuA4Kum54DELIWYaBNTBbfKlvlyKeRilpTh3a3I3rmy2ctn5HkKjGVmIv1WyIPNga3POZ28pxAEcQsVEFuU0fU/Bf9H5sDuj0i47JxzCBuimyFQEN1cMYwE5W7jz54hCEN3wC1blt9/M0U+jWqsC3psmlPb+qkj50ZriJb8bNoIHMutp+ERFy5CGrBJIiVIt8xvsJmkz9LuUhKDOTmwSN9yg9p+jrTD5L6B8yH8/WSu+4XMgK0QDv/BE/5eeLZcv6Q==",
+      "body": "{\n  \"Message\": \"Test Message OK: good example message\",\n  \"Details\": \"Test details\"  \n}",
+      "attributes": {
+        "ApproximateReceiveCount": "1",
+        "AWSTraceHeader": "Root=1-64495159-17ceb00068aada396a66bd23",
+        "SentTimestamp": "1682526553465",
+        "SenderId": "AROASECKEBOYZPRE774YO:BackplaneAssumeRoleSession",
+        "ApproximateFirstReceiveTimestamp": "1682526553466"
+      },
+      "messageAttributes": {},
+      "md5OfBody": "d46c3294a7ebf36b9a9a99f46b768a9d",
+      "eventSource": "aws:sqs",
+      "eventSourceARN": "arn:aws:sqs:us-east-1:12345678901:apigw-sqs-lambda-queue",
+      "awsRegion": "us-east-1"
+    }
+  ]
+}

lambda/tests/test_event_02_good_multiple.json

@@ -0,0 +1,38 @@
+{
+  "Records": [
+    {
+      "messageId": "4332b17c-b7cd-4aef-8dba-7cb7240e3d0e",
+      "receiptHandle": "AWEBZGy/Ajve1xtBoqIJhPmO0ANH9FWhcpjt7xevdsSw5+BK0OIljV8Jq/6SNgQ9boZKcTdGkK2aaiSo9iCAgsnSyUJ3u3FenB5rOnlOTf3ctMHHEJ4tGrwSR6lx8be8/CggdbtuCxjzZsPU2IUEIo4URuA4Kum54DELIWYaBNTBbfKlvlyKeRilpTh3a3I3rmy2ctn5HkKjGVmIv1WyIPNga3POZ28pxAEcQsVEFuU0fU/Bf9H5sDuj0i47JxzCBuimyFQEN1cMYwE5W7jz54hCEN3wC1blt9/M0U+jWqsC3psmlPb+qkj50ZriJb8bNoIHMutp+ERFy5CGrBJIiVIt8xvsJmkz9LuUhKDOTmwSN9yg9p+jrTD5L6B8yH8/WSu+4XMgK0QDv/BE/5eeLZcv6Q==",
+      "body": "{\n  \"Message\": \"Test Message OK: good example message 1\",\n  \"Details\": \"Test details\"  \n}",
+      "attributes": {
+        "ApproximateReceiveCount": "1",
+        "AWSTraceHeader": "Root=1-64495159-17ceb00068aada396a66bd23",
+        "SentTimestamp": "1682526553465",
+        "SenderId": "AROASECKEBOYZPRE774YO:BackplaneAssumeRoleSession",
+        "ApproximateFirstReceiveTimestamp": "1682526553466"
+      },
+      "messageAttributes": {},
+      "md5OfBody": "d46c3294a7ebf36b9a9a99f46b768a9d",
+      "eventSource": "aws:sqs",
+      "eventSourceARN": "arn:aws:sqs:us-east-1:12345678901:apigw-sqs-lambda-queue",
+      "awsRegion": "us-east-1"
+    },
+    {
+      "messageId": "4332b17c-b7cd-4aef-8dba-7cb7240e3d0e",
+      "receiptHandle": "AWEBZGy/Ajve1xtBoqIJhPmO0ANH9FWhcpjt7xevdsSw5+BK0OIljV8Jq/6SNgQ9boZKcTdGkK2aaiSo9iCAgsnSyUJ3u3FenB5rOnlOTf3ctMHHEJ4tGrwSR6lx8be8/CggdbtuCxjzZsPU2IUEIo4URuA4Kum54DELIWYaBNTBbfKlvlyKeRilpTh3a3I3rmy2ctn5HkKjGVmIv1WyIPNga3POZ28pxAEcQsVEFuU0fU/Bf9H5sDuj0i47JxzCBuimyFQEN1cMYwE5W7jz54hCEN3wC1blt9/M0U+jWqsC3psmlPb+qkj50ZriJb8bNoIHMutp+ERFy5CGrBJIiVIt8xvsJmkz9LuUhKDOTmwSN9yg9p+jrTD5L6B8yH8/WSu+4XMgK0QDv/BE/5eeLZcv6Q==",
+      "body": "{\n  \"Message\": \"Test Message OK: good example message 2\",\n  \"Details\": \"Test details\"  \n}",
+      "attributes": {
+        "ApproximateReceiveCount": "1",
+        "AWSTraceHeader": "Root=1-64495159-17ceb00068aada396a66bd23",
+        "SentTimestamp": "1682526553465",
+        "SenderId": "AROASECKEBOYZPRE774YO:BackplaneAssumeRoleSession",
+        "ApproximateFirstReceiveTimestamp": "1682526553466"
+      },
+      "messageAttributes": {},
+      "md5OfBody": "d46c3294a7ebf36b9a9a99f46b768a9d",
+      "eventSource": "aws:sqs",
+      "eventSourceARN": "arn:aws:sqs:us-east-1:12345678901:apigw-sqs-lambda-queue",
+      "awsRegion": "us-east-1"
+    }
+  ]
+}

lambda/tests/test_event_03_bad.json

@@ -0,0 +1,21 @@
+{
+  "Records": [
+    {
+      "messageId": "4332b17c-b7cd-4aef-8dba-7cb7240e3d0e",
+      "receiptHandle": "AWCBZGy/Ajve1xtBoqIJhPmO0ANH9FWhcpjt7xevdsSw5+BK0OIljV8Jq/6SNgQ9boZKcTdGkK2aaiSo9iCAgsnSyUJ3u3FenB5rOnlOTf3ctMHHEJ4tGrwSR6lx8be8/CggdbtuCxjzZsPU2IUEIo4URuA4Kum54DELIWYaBNTBbfKlvlyKeRilpTh3a3I3rmy2ctn5HkKjGVmIv1WyIPNga3POZ28pxAEcQsVEFuU0fU/Bf9H5sDuj0i47JxzCBuimyFQEN1cMYwE5W7jz54hCEN3wC1blt9/M0U+jWqsC3psmlPb+qkj50ZriJb8bNoIHMutp+ERFy5CGrBJIiVIt8xvsJmkz9LuUhKDOTmwSN9yg9p+jrTD5L6B8yH8/WSu+4XMgK0QDv/BE/5eeLZcv6Q==",
+      "body": "{\n  \"MessageIntentionalWrongKey\": \"Test Message NOT OK: good example message with wrong keys\"\n}",
+      "attributes": {
+        "ApproximateReceiveCount": "1",
+        "AWSTraceHeader": "Root=1-64495159-17ceb00068aada396a66bd23",
+        "SentTimestamp": "1682526553465",
+        "SenderId": "AROASECKEBOYZPRE774YO:BackplaneAssumeRoleSession",
+        "ApproximateFirstReceiveTimestamp": "1682526553466"
+      },
+      "messageAttributes": {},
+      "md5OfBody": "d46c3294a7ebf36b9a9a99f46b768a9d",
+      "eventSource": "aws:sqs",
+      "eventSourceARN": "arn:aws:sqs:us-east-1:12345678901:apigw-sqs-lambda-queue",
+      "awsRegion": "us-east-1"
+    }
+  ]
+}

lambda/tests/test_lambda_function.py

@@ -0,0 +1,80 @@
+# Built-in imports
+import os, sys
+import json
+import unittest
+
+# External imports
+from aws_lambda_powertools.utilities.data_classes import event_source, SQSEvent
+from moto import mock_sts
+
+# Add path to find lambda directory for own imports
+sys.path.append(os.path.abspath(os.path.dirname(os.path.dirname(__file__))))
+
+# Own imports
+import src.lambda_function as _lambda  # noqa: E402
+
+
+class TestLambdaFunction(unittest.TestCase):
+    """
+    TestCase for unit testing the inner Lambda Function functionalities.
+    """
+
+    def load_test_event(self, test_event_name: str) -> dict:
+        """
+        Load test event from given file.
+        """
+        path_to_event = os.path.join(
+            os.path.dirname(__file__),
+            test_event_name,
+        )
+        with open(path_to_event) as file:
+            test_event = json.load(file)
+        return test_event
+
+    # The "mock_sts" decorator allows to "mock/fake" the sts API calls for tests
+    @mock_sts()
+    def test_process_messages_success_single(self):
+        """
+        Test successful process_messages call for a single message.
+        """
+        # Load pre-configured event for current test case
+        event = self.load_test_event("test_event_01_good_single.json")
+
+        # Middleware to load event with correct SQSEvent data class
+        event_sqs = SQSEvent(event)
+        result = _lambda.process_messages(event_sqs)
+
+        self.assertEqual(result, True)
+
+    @mock_sts()
+    def test_process_messages_success_multiple(self):
+        """
+        Test successful process_messages call for multiple messages.
+        """
+        # Load pre-configured event for current test case
+        event = self.load_test_event("test_event_02_good_multiple.json")
+
+        # Middleware to load event with correct SQSEvent data class
+        event_sqs = SQSEvent(event)
+        result = _lambda.process_messages(event_sqs)
+
+        self.assertEqual(result, True)
+
+    @mock_sts()
+    def test_process_messages_error(self):
+        """
+        Test errors on process_messages call due to wrong message format.
+        """
+        # Load pre-configured event for current test case
+        event = self.load_test_event("test_event_03_bad.json")
+
+        # Middleware to load event with correct SQSEvent data class
+        event_sqs = SQSEvent(event)
+
+        # Expected an exception intentionally, otherwise fails
+        with self.assertRaises(Exception):
+            _lambda.process_messages(event_sqs)
+
+
+if __name__ == "__main__":
+    unittest.main()