Simple Localstack Step Function Mock example

1. Start LocalStack, loading the Mock Configuration File

LOCALSTACK_SFN_MOCK_CONFIG=/tmp/MockConfigFile.json localstack start --volume $PWD/MockConfigFi
le.json:/tmp/MockConfigFile.json

2. Deploy the application

cdklocal bootstrap

cdklocal deploy --require-approval=never 

3. Invoke the state machine, specifying the test case name using a special ARN suffix:

awslocal stepfunctions start-execution \
    --state-machine arn:aws:states:us-east-1:000000000000:stateMachine:MyStateMachine#BaseCase \
    --input '{"name": "John", "surname": "smith"}' \
    --name "MockExecutionBaseCase" --region us-east-1

⚠️ The test case name (BaseCase) must match the name of the test case in MockConfigFile.json. Otherwise, LocalStack will try to invoke a real Lambda function, which does not exist!

📌 See Run Test Cases with Mocked Integrations in the LocalStack documentation.