Local testing of CDK-defined Step Functions state machine

CDK-defined state machine

CDK ?

State machine definition

CDK2ASL

1. Using outputs

{
“DirectBankAccountCreation”: {
workflowStateMachineDefinitionE0E0A7BF”: “{\”StartAt\”:\”Input checks\”,\”States\”:{\”Input checks\”:{\”Type\”:\”Parallel\”,\”Next\”:\”Create User\”,\”Branches\”:[{\”StartAt\”:\”Extract info from ID\”,\”States\”:{\”Extract info from ID\”:{\”Next\”:\”Crosscheck Identity\”,\”Retry\”:...\”User created, account creation initiated\”:{\”Type\”:\”Succeed\”}}}”, “userCreationAPIBankAccountCreationApiEndpoint1A0514D2”: “https://9xko5dgqbf.execute-api.eu-west-1.amazonaws.com/prod/"
}
}
jq -r ‘.DirectBankAccountCreation|with_entries(select(.key | startswith(“workflowStateMachineDefinition”))) | to_entries | .[].value’ cdk.out/output.json > cdk.out/state_machine.asl.json

2. Using a 3rd party tool

Step Functions local

Mocked Service Integrations

Unit Testing dependencies not being mocker
Unit tests should be independent from external factors

Starting Step Functions local 🚀

docker run -p 8083:8083 -d --rm --name stepfunctions-local \
--mount type=bind,readonly,source=$(ROOT_DIR)/test/MockConfigFile.json,destination=/home/StepFunctionsLocal/MockConfigFile.json \
-e SFN_MOCK_CONFIG=”/home/StepFunctionsLocal/MockConfigFile.json” \ amazon/aws-stepfunctions-local

Creating the state machine

aws stepfunctions create-state-machine \
--endpoint-url http://localhost:8083 \
# we can also use the asl-0.json file here
--definition file://cdk.out/state_machine.asl.json \
--name “DirectIntegrationTest” \
--role-arn “arn:aws:iam::123456789012:role/DummyRole” \
--no-cli-pager

Tests

Unit tests, Unit tests everywhere

Setup

Unit tests

Conclusion

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