AWS CDK TESTER (CDK CUSTOM CONSTRUCT)

It's Custom Construct internally using StepFunctions and it's for test things with lambda functions.

Tester execute multiple testCases in parallel at once.
Each testCase has multiple steps(1 step = 1 lambda function) in sequential
(When lambda return any value, it will be passed as event.body to next step's lambda).

When lambda function throws error, the testCase is considered as fail.
When the testCase's steps are all passed(do not throw any error), the testCase is considered as pass.

So, When 1 or more testCase(with required: true) got fail, the whole test considered as FAILED.
Otherwise, It will be considered as SUCCEEDED.

TESTCASE EXAMPLE

Step1. Publish Sns (In lambda, return expected value that should be put into Dynamodb. It will be passed to Step2's lambda function as event.body.)
Step2. Check if Dynamodb item has correctly put within 5 seconds.(use any assertion library in lambda.)

testCases: [
      {
         id: 'Test1',
         steps: [
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'sns-publish'),
            },
            {
               interval: Duration.seconds(5),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'check-dynamodb'),
            },
         ],
      },
   ],

It has two modes. TestInDeployment and TestInEvent.

TestOnDeployment

TestOnDeployment do test in stack deployment(Internally using stepfunctions, lambdas, custom-resource).
When the test has FAILED, stack deployment will be failed, and the stack will be rollbacked.
You can use it for neccessary integration test during stack deployment.

It offers optional properties, logGroup(Log test result automatically in each test).

new TestOnDeployment(this, 'TestOnDeployment', {
   logGroup: new aws_logs.LogGroup(this, 'LogGroup'),
   totalTimeout: Duration.hours(1),
   testCases: [
      {
         id: 'TestOnDeployment-test1',
         required: false,
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test1-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test1-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test1-step3'),
            },
         ],
      },
      {
         id: 'TestOnDeployment-test2',
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test2-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test2-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test2-step3'),
            },
         ],
      },
      {
         id: 'TestOnDeployment-test3',
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test3-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test3-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnDeployment-test3-step3'),
            },
         ],
      },
   ],
});

TestOnEvent

TestOnEvent do test in scheduled date(Internally using stepfunctions, lambdas, eventbridge scheduler, custom-resource).
You can use it for regular tests in specific time.

It offers optional properties, logGroup(Log test result automatically in each test),
snsTopic(Publish when test done),
snsTopicWhenError(Publish when test could not finished because of an error(ex. TIMED_OUT)).

new TestOnEvent(this, 'TestOnEvent', {
   snsTopic: new aws_sns.Topic(this, 'SnsTopic'),
   snsTopicWhenError: new aws_sns.Topic(this, 'SnsTopicWhenError'),
   logGroup: new aws_logs.LogGroup(this, 'LogGroup'),
   schedule: aws_events.Schedule.rate(Duration.hours(1)),
   testCases: [
      {
         id: 'TestOnEvent-test1',
         required: false,
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test1-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test1-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test1-step3'),
            },
         ],
      },
      {
         id: 'TestOnEvent-test2',
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test2-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test2-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test2-step3'),
            },
         ],
      },
      {
         id: 'TestOnEvent-test3',
         steps: [
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test3-step1'),
            },
            {
               interval: Duration.seconds(3),
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test3-step2'),
            },
            {
               lambdaFunction: new aws_lambda_nodejs.NodejsFunction(this, 'TestOnEvent-test3-step3'),
            },
         ],
      },
   ],
});

You can use SNS topic subscription filter with message attributes.

• For snsTopic

messageAttributes: {
   status: 'SUCCEEDED' | 'FAILED';
   // number of total testCases
   total: number;
   // number of passed only testCases
   pass: number;
   // number of failed only testCases(total)
   failTotal: number;
   // number of failed only testCases(with required:true)
   failRequired: number;
   // number of failed only testCases(with required:false)
   failOptional: number;
}

• For snsTopicWhenError

messageAttributes: {
   status: 'FAILED' | 'TIMED_OUT';
}