Adding additional lambda local pytest

python-test-samples/README.md

@@ -10,6 +10,8 @@ This portion of the repository contains code samples for testing serverless appl
 |[Python Starter Project](./apigw-lambda)|This project contains introductory examples of Python tests written for AWS Lambda. This is the best place to start!|
 |[Integrated Application Test Kit](./integrated-application-test-kit)|This sample demonstrates how you can use the [AWS Integrated Application Test Kit (IATK)](https://awslabs.github.io/aws-iatk/) to develop integration tests for your serverless and event-driven applications.|
 |[Lambda local testing with Mocks](./lambda-mock)|This project contains unit tests for Lambda using mocks.|
+|[Lambda hello world local testing](./lambda-sam-helloworld)|This project contains unit pytest tests for Hello World Lambda.|
+|[Lambda Layers local testing](./lambda-sam-layers)|This project contains unit pytests tests for Lambda building layers.|
 |[Lambda Layers with Mocks](./apigw-lambda-layer)|This project contains unit tests for Lambda layers using mocks.|
 |[API Gateway with Lambda and DynamoDB](./apigw-lambda-dynamodb)|This project contains unit and integration tests for a pattern using API Gateway, AWS Lambda and Amazon DynamoDB.|
 |[Schema and Contract Testing](./schema-and-contract-testing)|This project contains sample schema and contract tests for an event driven architecture.|

python-test-samples/lambda-sam-helloworld/README.md

@@ -0,0 +1,349 @@
+[![python: 3.9](https://img.shields.io/badge/Python-3.9-green)](https://img.shields.io/badge/Python-3.9-green)
+[![AWS: Lambda](https://img.shields.io/badge/AWS-Lambda-orange)](https://img.shields.io/badge/AWS-Lambda-orange)
+[![test: pytest](https://img.shields.io/badge/Test-Pytest-red)](https://img.shields.io/badge/Test-Pytest-red)
+[![test: local](https://img.shields.io/badge/Test-Local-red)](https://img.shields.io/badge/Test-Local-red)
+
+# Local Testing: AWS Lambda Hello World
+
+## Introduction
+
+This project demonstrates how to test AWS Lambda functions locally using the SAM CLI and PyTest. It provides a comprehensive Hello World example that showcases local testing capabilities without requiring actual AWS infrastructure, including automated test execution and validation.
+
+---
+
+## Contents
+
+- [Local Testing: AWS Lambda Hello World with PyTest](#local-testing-aws-lambda-hello-world-with-pytest)
+  - [Introduction](#introduction)
+  - [Contents](#contents)
+  - [Architecture Overview](#architecture-overview)
+  - [Project Structure](#project-structure)
+  - [Prerequisites](#prerequisites)
+  - [Test Scenarios](#test-scenarios)
+  - [About the Test Process](#about-the-test-process)
+  - [Testing Workflows](#testing-workflows)
+  - [Common Issues](#common-issues)
+  - [Additional Resources](#additional-resources)
+
+---
+
+## Architecture Overview
+
+<p align="center">
+  <img src="img/lambda-sam-helloworld.png" alt="AWS Lambda Hello World" width="300"/>
+</p>
+
+Components:
+
+- Python Hello World Lambda function
+- SAM CLI for local Lambda emulation
+- PyTest framework for automated testing
+- Test events for various invocation scenarios
+
+---
+
+## Project Structure
+
+```
+├── events/                                     _# folder containing json files for Lambda input events_
+│   ├── lambda-helloworld-event.json            _# basic Hello World event_
+│   └── lambda-helloworld-custom-event.json     _# custom message event_
+├── img/lambda-sam-helloworld.png               _# Architecture diagram_
+├── lambda_helloworld_src/                      _# folder containing Lambda function source code_
+│   └── app.py                                  _# main Lambda handler function_
+├── tests/
+│   ├── unit/src/test_lambda_local.py           _# python PyTest test definition_
+│   └── requirements.txt                        _# pytest pip requirements dependencies file_
+├── template.yaml                               _# sam yaml template file for Lambda function_
+└── README.md                                   _# instructions file_
+```
+
+---
+
+## Prerequisites
+
+- AWS SAM CLI
+- Docker
+- Python 3.9 or newer
+- AWS CLI v2 (for debugging)
+- Basic understanding of AWS Lambda
+- Basic understanding of PyTest framework
+
+---
+
+## Test Scenarios
+
+### 1. Basic Hello World
+
+- Tests the basic Lambda function invocation
+- Validates the default "Hello World!" message response
+- Verifies correct HTTP status code (200)
+- Used to validate the basic functionality of the Lambda function
+
+### 2. Custom Message Handling
+
+- Tests the Lambda function with custom input parameters
+- Validates that the function can process and return custom messages
+- Verifies proper input parameter handling and response formatting
+
+### 3. Error Handling
+
+- Tests the Lambda function's behavior with invalid or missing input
+- Validates error responses and proper exception handling
+- Ensures graceful degradation when unexpected input is provided
+
+---
+
+## About the Test Process
+
+The test process leverages PyTest fixtures to manage the lifecycle of the SAM Local Lambda emulator:
+
+1. **SAM Local Setup**: The `lambda_container` fixture verifies that SAM Local Lambda emulator is available and running on the expected port (3001).
+
+2. **Lambda Client Creation**: The `lambda_client` fixture creates a Boto3 Lambda client configured to connect to the local SAM emulator endpoint.
+
+3. **Test Execution**: Each test invokes the Lambda function using the local client with different event payloads and validates:
+   - Response structure and format
+   - Status codes
+   - Response body content
+   - Execution metadata
+
+4. **Validation**: Tests verify that:
+   - The Lambda function executes successfully
+   - Response contains expected message content
+   - HTTP status codes are correct
+   - Response format matches API Gateway integration format
+
+5. **Cleanup**: After tests complete, the SAM Local process is gracefully terminated.
+
+---
+
+## Testing Workflows
+
+### Setup Docker Environment
+
+> Make sure Docker engine is running before running the tests.
+
+```shell
+lambda-sam-helloworld$ docker version
+Client: Docker Engine - Community
+ Version:           24.0.6
+ API version:       1.43
+(...)
+```
+
+### Run the Unit Test - End to end python test
+
+> Start the SAM Local Lambda emulator in a separate terminal:
+
+```shell
+lambda-sam-helloworld$
+sam local start-lambda -p 3001 &
+```
+
+> Set up the python environment:
+
+```shell
+lambda-sam-helloworld$ cd tests
+export AWS_ACCESS_KEY_ID='DUMMYIDEXAMPLE'
+export AWS_SECRET_ACCESS_KEY='DUMMYEXAMPLEKEY'
+export AWS_REGION='us-east-1'
+python3 -m venv venv
+source venv/bin/activate
+pip install --upgrade pip
+pip install -r requirements.txt
+```
+
+#### Run the Unit Tests
+
+```shell
+lambda-sam-helloworld/tests$
+python3 -m pytest -s unit/src/test_lambda_local.py
+```
+
+Expected output:
+
+```
+lambda-sam-helloworld/tests$
+python3 -m pytest -s unit/src/test_lambda_local.py
+================================================================= test session starts =================================================================
+platform linux -- Python 3.10.12, pytest-7.4.4, pluggy-1.6.0
+benchmark: 4.0.0 (defaults: timer=time.perf_counter disable_gc=False min_rounds=5 min_time=0.000005 max_time=1.0 calibration_precision=10 warmup=False warmup_iterations=100000)
+rootdir: /home/ubuntu/environment/serverless-test-samples_lambda_pytest_try1/python-test-samples/lambda-sam-helloworld/tests
+plugins: mock-3.11.1, timeout-2.1.0, Faker-24.4.0, xdist-3.3.1, metadata-3.1.1, benchmark-4.0.0, cov-4.1.0, html-3.2.0
+collected 9 items                                                                                                                                                               
+
+unit/src/test_lambda_local.py SAM Local Lambda emulator is running on port 3001
+Lambda function is responding correctly
+Lambda response: {'StatusCode': 200, 'Payload': '{"statusCode": 200, "body": "{\"message\": \"Hello World! This is local Run!\"}"}'}
+.Lambda response: {'StatusCode': 200, 'Message': 'Hello World! This is local Run!', 'Input_Handled': True}
+.Lambda response: {'StatusCode': 200, 'Scenarios_Tested': 6, 'All_Handled_Gracefully': True}
+.Lambda response format validation passed - matches API Gateway integration format
+.Performance metrics:
+  Cold start: 403ms
+  Warm start average: 423ms
+  Performance improvement: False
+Performance test completed: avg=416ms, min=403ms, max=424ms
+.Concurrent invocations test passed
+Results: Success_Rate=100.0%, Avg_Execution_Time=1328ms, Successful=5/5
+.Response metadata available: ['HTTPStatusCode', 'HTTPHeaders', 'RetryAttempts']
+Resource usage test passed - payload size: 81 bytes, response efficiency validated
+.Edge cases test passed - 5 scenarios handled gracefully
+.JSON serialization test passed - proper JSON handling validated
+.
+================================================================= 9 passed in 12.83s ===================================================================
+
+```
+#### Clean up section
+
+> clean pyenv environment
+
+```sh
+lambda-sam-helloworld/tests$
+deactivate
+rm -rf venv/
+```
+
+> unsetting variables
+
+```sh
+unset AWS_ACCESS_KEY_ID
+unset AWS_SECRET_ACCESS_KEY
+unset AWS_REGION
+```
+
+> cleaning sam process
+
+```sh
+ps -axuf | grep '[s]am local start-lambda' | awk '{print $2}' | xargs -r kill
+```
+
+#### Debug - PyTest Debugging
+
+For more detailed debugging in pytest:
+
+```sh
+# Run with verbose output
+python3 -m pytest -s -v unit/src/test_lambda_local.py
+
+# Run with debug logging
+python3 -m pytest -s -v unit/src/test_lambda_local.py --log-cli-level=DEBUG
+
+# Run a specific pytest test
+python3 -m pytest -s -v unit/src/test_lambda_local.py::test_lambda_basic_hello_world
+```
+
+---
+
+### Fast local development for Lambda Functions
+
+#### AWS CLI Commands for Manual Verification
+
+If you need to manually verify the Lambda function execution, you can use these commands:
+
+#### Configure environment variables
+
+```sh
+lambda-sam-helloworld$
+export AWS_ACCESS_KEY_ID='DUMMYIDEXAMPLE'
+export AWS_SECRET_ACCESS_KEY='DUMMYEXAMPLEKEY'
+export AWS_REGION='us-east-1'
+```
+
+#### Start Lambda emulator
+
+```sh
+lambda-sam-helloworld$
+sam local start-lambda -p 3001 &
+```
+
+#### Debug lambda functions - Manual Lambda Testing
+
+```sh
+# Test Basic Hello World
+lambda-sam-helloworld$
+aws lambda invoke \
+    --function-name LambdaHelloWorld \
+    --endpoint-url http://127.0.0.1:3001 \
+    --payload fileb://events/lambda-helloworld-event.json \
+    output.txt
+cat output.txt
+
+# Test Custom Message
+lambda-sam-helloworld$
+aws lambda invoke \
+    --function-name LambdaHelloWorld \
+    --endpoint-url http://127.0.0.1:3001 \
+    --payload fileb://events/lambda-helloworld-custom-event.json \
+    output.txt
+cat output.txt
+```
+
+#### Direct SAM Local Invoke
+
+```sh
+# Basic invocation
+sam local invoke LambdaHelloWorld \
+    --event events/lambda-helloworld-event.json
+
+# Custom message invocation
+sam local invoke LambdaHelloWorld \
+    --event events/lambda-helloworld-custom-event.json
+
+# Debug mode with container logs
+sam local invoke LambdaHelloWorld \
+    --event events/lambda-helloworld-event.json \
+    --debug
+```
+
+---
+
+## Common Issues
+
+### SAM Local Connection Issues
+
+If tests are skipped with "Lambda invocation failed, SAM might not be running properly":
+
+- Ensure SAM Local is running on port 3001
+- Check that you've started SAM with the correct template.yaml file
+- Verify the Lambda function name matches the template definition
+- Check SAM logs for any errors with `sam local start-lambda --debug`
+
+### Lambda Function Import Issues
+
+If the Lambda function fails to import or execute:
+
+- Verify the Python runtime version matches your local environment
+- Check that all required dependencies are included in the function package
+- Ensure the handler path is correctly specified in template.yaml
+- Review the Lambda function logs in the SAM Local output
+
+### Port Conflicts
+
+If SAM Local fails to start due to port conflicts:
+
+- Check if port 3001 is already in use with `lsof -i :3001`
+- Use a different port with `sam local start-lambda -p 3002`
+- Update your test configuration to match the new port
+
+### Docker Container Issues
+
+If Docker containers fail to start or behave unexpectedly:
+
+- Ensure Docker daemon is running and accessible
+- Check Docker permissions for your user account
+- Verify sufficient disk space for container images
+- Try pulling the latest Lambda runtime images manually
+
+---
+
+## Additional Resources
+
+- [SAM CLI Documentation](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-command-reference.html)
+- [AWS Lambda Developer Guide](https://docs.aws.amazon.com/lambda/latest/dg/welcome.html)
+- [SAM Local Lambda Testing Guide](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-using-invoke.html)
+- [PyTest Documentation](https://docs.pytest.org/)
+- [AWS Lambda Python Runtime](https://docs.aws.amazon.com/lambda/latest/dg/lambda-python.html)
+- [SAM Template Specification](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-specification.html)
+
+[Top](#contents)

python-test-samples/lambda-sam-helloworld/events/lambda-helloworld-custom-event.json

@@ -0,0 +1,21 @@
+{
+    "test_type": "custom_message",
+    "custom_field": "test_value",
+    "user_name": "TestUser",
+    "timestamp": "2024-07-31T10:00:00Z",
+    "nested_object": {
+        "key1": "value345",
+        "key2": 123
+    },
+    "array_field": [1, 2, 3, "string", true, null],
+    "settings": {
+        "language": "en",
+        "region": "us-east-1",
+        "debug": true
+    },
+    "metadata": {
+        "source": "custom_event",
+        "version": "1.0",
+        "environment": "local"
+    }
+}

python-test-samples/lambda-sam-helloworld/events/lambda-helloworld-event.json

@@ -0,0 +1,5 @@
+{
+  "key1": "value1",
+  "key2": "value2",
+  "key3": "value3"
+}

python-test-samples/lambda-sam-helloworld/lambda_helloworld_src/app.py

@@ -0,0 +1,7 @@
+import json
+def lambda_handler(event, context):
+    return {
+        "statusCode": 200,
+        "body": json.dumps({
+          "message" : "Hello World! This is local Run!"}),
+    }