@aws-cdk/assert

Testing utilities and assertions for CDK libraries

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This is a developer preview (public beta) module. Releases might lack important features and might have future breaking changes.

This API is still under active development and subject to non-backward compatible changes or removal in any future version. Use of the API is not recommended in production environments. Experimental APIs are not subject to the Semantic Versioning model.

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This library contains helpers for writing unit tests and integration tests for CDK libraries

Unit tests

Write your unit tests like this:

const stack = new Stack();

new MyConstruct(stack, 'MyConstruct', {
    ...
});

expect(stack).to(someExpectation(...));

Here are the expectations you can use:

Verify (parts of) a template

Check that the synthesized stack template looks like the given template, or is a superset of it. These functions match logical IDs and all properties of a resource.

matchTemplate(template, matchStyle)
exactlyMatchTemplate(template)
beASupersetOfTemplate(template)

Example:

expect(stack).to(beASupersetOfTemplate({
    Resources: {
        HostedZone674DD2B7: {
            Type: "AWS::Route53::HostedZone",
            Properties: {
                Name: "test.private.",
                VPCs: [{
                    VPCId: { Ref: 'VPC06C5F037' },
                    VPCRegion: { Ref: 'AWS::Region' }
                }]
            }
        }
    }
}));

Check existence of a resource

If you only care that a resource of a particular type exists (regardless of its logical identifier), and that some of its properties are set to specific values:

haveResource(type, subsetOfProperties)

Example:

expect(stack).to(haveResource('AWS::CertificateManager::Certificate', {
    DomainName: 'test.example.com',
    // Note: some properties omitted here

    ShouldNotExist: ABSENT
}));

ABSENT is a magic value to assert that a particular key in an object is not set (or set to undefined).

Check number of resources

If you want to assert that n number of resources of a particular type exist, with or without specific properties:

countResources(type, count)
countResourcesLike(type, count, props)

Example:

expect(stack).to(countResources('AWS::ApiGateway::Method', 3));
expect(stack).to(countResourcesLike('AWS::ApiGateway::Method', 1, {
  HttpMethod: 'GET',
  ResourceId: {
    "Ref": "MyResource01234"
  }
}));

Check existence of an output

haveOutput assertion can be used to check that a stack contains specific output. Parameters to check against can be:

• outputName
• outputValue
• exportName

If outputValue is provided, at least one of outputName, exportName should be provided as well

Example

expect(synthStack).to(haveOutput({
  outputName: 'TestOutputName',
  exportName: 'TestOutputExportName',
  outputValue: {
    'Fn::GetAtt': [
      'TestResource',
      'Arn'
    ]
  }
}));

Changelog

1.24.0 (2020-02-13)

Features

• assert: add countResourcesLike method (#6168) (491e2d9)
• cx-api: clean up features.ts (#6181) (efd6f3d), closes #6098
• dynamodb: add metrics for dynamodb table (#6149) (295391e)
• dynamodb: global tables version 2019.11.21 (#5821) (8c0c2b1), closes #5752
• ec2: smarter default for VPN route propagation (#6071) (5dd8aca), closes #6008
• ec2: VPC flow logs (a2fddec), closes #3493
• iam: add ability to create IAM role descriptions (cee8825)
• iam: descriptions for IAM Roles (a1294d3)
• cfnspec: update CloudFormation spec to 10.5.0 (#6195) (47a9949)
• iam: lookup ManagedPolicy via ARN (2df2023), closes #6186
• lambda: expose function.deadLetterQueue (6656047), closes #6170
• step-functions: grantStartExecution available on imported StateMachine (5ae81cd), closes #6173
• stepfunctions: EMR service integrations (c69b6d2), closes #5224

Bug Fixes

• cli: truncated 'cdk diff' output in pipes (aba1485)
• apigateway: deployment fails when Model's contentType is not specified (#6199) (0bf1403), closes #6161
• apigateway: stack deployment fails when a Stage is explicitly specified (#6165) (879601e), closes #6068
• cli: wrongly assume aws config file always exists (#6196) (23f8b9f)
• codebuild: badge is not allowed for CodeCommit sources (#6211) (433d957), closes #6205
• ec2: onePerAz does not work for looked-up VPCs (3332d06), closes #3126
• ecs-patterns: allow imported load balancers as inputs (7f8c90d)
• elasticloadbalancingv2: logAccessLogs in Base Load Balancer (#6197) (adbc3b9), closes #3794
• elbv2: validate rule priority is a positive number (#6222) (1fbaafe), closes #3794
• kms: add TagResource & UntagResource IAM permissions to default key policy (#6125) (e65a326), closes #6102