AWS-CDK How to test props with Fine-grained assertions - amazon-web-services

Question

How can I test all the props passed to the s3.Bucket?
I would like to test all the props passed to the s3.Bucket (no Snapshot).
The test is giving me an error on WebsiteConfiguration ...
To check how to write the prop obj inside the toHaveResource fn i used this doc
Anyone could help me?
import * as cdk from "#aws-cdk/core";
import * as s3 from "#aws-cdk/aws-s3";
export class S3CdkStack extends cdk.Stack {
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
super(scope, id, props);
new s3.Bucket(this, "ReactGitHubActionBucket", {
versioned: true,
publicReadAccess: true,
websiteIndexDocument: "index.html",
removalPolicy: cdk.RemovalPolicy.DESTROY,
autoDeleteObjects: true,
});
}
}
import { expect as expectCDK, haveResource } from '#aws-cdk/assert';
import * as cdk from '#aws-cdk/core';
import * as Stacks from '../lib/s3-cdk-stack';
test('First test', () => {
const app = new cdk.App();
const stack = new Stacks.S3CdkStack(app, 'S3CdkTestStack');
expectCDK(stack).to(haveResource("AWS::S3::Bucket",{
VersioningConfiguration: {
Status: "Enabled"
},
WebsiteConfiguration: {
IndexDocument: "index.html"
}
}))
});
$ jest
FAIL test/stacks.test.ts
✕ First test (68 ms)
● First test
None of 1 resources matches resource 'AWS::S3::Bucket' with {
"$objectLike": {
"VersioningConfiguration": {
"Status": "Enabled"
},
"WebsiteConfiguration": {
"IndexDocument": "index.html"
}
}
}.
- Field WebsiteConfiguration missing in:
{
"Type": "AWS::S3::Bucket",
"Properties": {
"VersioningConfiguration": {
"Status": "Enabled"
}
},
"UpdateReplacePolicy": "Retain",
"DeletionPolicy": "Retain"
}

Answer 1

It may have been updated since you wrote your question, but as of CDK 1.113.0 the following example works for me.
Note that my imports are slightly different to yours, and that I've used .toHaveResource() instead of .to(haveResource()).
// CDK version: 1.113.0
import '#aws-cdk/assert/jest';
import * as cdk from '#aws-cdk/core';
import * as s3 from '#aws-cdk/aws-s3';
// Included for completeness, but you'd import this:
class S3CdkStack extends cdk.Stack {
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
super(scope, id, props);
new s3.Bucket(this, 'ReactGitHubActionBucket', {
versioned: true,
publicReadAccess: true,
websiteIndexDocument: 'index.html',
removalPolicy: cdk.RemovalPolicy.DESTROY,
autoDeleteObjects: true,
});
}
}
// This test should pass:
test('Test complete S3 bucket configuration', () => {
const app = new cdk.App();
const stack = new S3CdkStack(app, 'S3CdkTestStack');
// ↓↓↓↓↓↓↓↓↓↓↓↓↓↓
expect(stack).toHaveResource('AWS::S3::Bucket', {
VersioningConfiguration: {
Status: 'Enabled',
},
WebsiteConfiguration: {
IndexDocument: 'index.html',
},
});
});
Bonus tip: .toHaveResourceLike()
.toHaveResource() works well when the resource property value you're checking is simple (ie. a scalar value like a string or a number), but if it's more complex you should look into .toHaveResourceLike() which unfortunately isn't very well documented (link to the v1.113.0 source).
For example, the CloudFormation template you've created via the S3CdkStack() class above contains a Lambda function with the following Description property:
{
"Resources": {
"CustomS3AutoDeleteObjectsCustomResourceProviderHandler9D90184F": {
"Type": "AWS::Lambda::Function",
"Properties": {
"Description": {
"Fn::Join": [
"",
[
"Lambda function for auto-deleting objects in ",
{
"Ref": "ReactGitHubActionBucket1CE57800"
},
" S3 bucket."
]
]
}
}
}
}
}
Testing for the existence of "auto-deleting" in that description (just as an expository example) with .toHaveResource() would require including the whole description object, which is fragile and contains what looks like a hash...
In this case it's much better to use .toHaveResourceLike() and check only the part of the object you're interested in testing:
test('Test a subset of the Lambda description', () => {
const app = new cdk.App();
const stack = new S3CdkStack(app, 'S3CdkTestStack');
// ↓↓↓↓
expect(stack).toHaveResourceLike('AWS::Lambda::Function', {
// Only need to include the subset of
// the value object you're testing:
Description: {
'Fn::Join': [
'',
['Lambda function for auto-deleting objects in '],
],
},
});
});