feat(integ-tests): add IntegTest to group test cases (aws#20015)

Add a new construct, `IntegTest` that contains a list of `IntegTestCase`s. This new construct is now responsible for starting the synthesis of the manifests. Previously, it was `IntegTestCase` that did this. But this results in the last `IntegTestCase` to be synthesized to override all other test cases.

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [ ] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/integ-tests/README.md

@@ -23,7 +23,7 @@ certain handler:
 
 ```ts
 interface StackUnderTestProps extends StackProps {
-  functionProps?: lambda.FunctionProps;
+  architecture?: lambda.Architecture;
 }
 
 class StackUnderTest extends Stack {
@@ -34,7 +34,7 @@ class StackUnderTest extends Stack {
       runtime: lambda.Runtime.NODEJS_12_X,
       handler: 'index.handler',
       code: lambda.Code.fromAsset(path.join(__dirname, 'lambda-handler')),
-      ...props.functionProps,
+      architecture: props.architecture,
     });
   }
 }
@@ -67,7 +67,8 @@ class StackUnderTest extends Stack {
 const app = new App();
 
 const stack = new Stack(app, 'stack');
-new IntegTestCase(stack, 'DifferentArchitectures', {
+
+const differentArchsCase = new IntegTestCase(stack, 'DifferentArchitectures', {
   stacks: [
     new StackUnderTest(app, 'Stack1', {
       architecture: lambda.Architecture.ARM_64,
@@ -77,6 +78,13 @@ new IntegTestCase(stack, 'DifferentArchitectures', {
     }),
   ],
 });
+
+// There must be exactly one instance of TestCase per file
+new IntegTest(app, 'integ-test', {
+
+  // Register as many test cases as you want here
+  testCases: [differentArchsCase],
+});
 ```
 
 This is all the instruction you need for the integration test runner to know
@@ -90,7 +98,7 @@ const stackUnderTest = new Stack(app, 'StackUnderTest', /* ... */);
 
 const stack = new Stack(app, 'stack');
 
-new IntegTestCase(stack, 'CustomizedDeploymentWorkflow', {
+const testCase = new IntegTestCase(stack, 'CustomizedDeploymentWorkflow', {
   stacks: [stackUnderTest],
   diffAssets: true,
   stackUpdateWorkflow: true,
@@ -108,5 +116,9 @@ new IntegTestCase(stack, 'CustomizedDeploymentWorkflow', {
     },
   },
 });
+
+new IntegTest(app, 'integ-test', {
+  testCases: [testCase],
+});
 ```
 

packages/@aws-cdk/integ-tests/lib/manifest-synthesizer.ts

@@ -0,0 +1,30 @@
+import { IntegManifest, Manifest } from '@aws-cdk/cloud-assembly-schema';
+import { ISynthesisSession } from '@aws-cdk/core';
+import { IntegManifestWriter } from './manifest-writer';
+import { IntegTestCase } from './test-case';
+
+const emptyManifest: IntegManifest = {
+  version: '',
+  testCases: { },
+};
+
+export class IntegManifestSynthesizer {
+  constructor(private readonly testCases: IntegTestCase[]) {}
+
+  synthesize(session: ISynthesisSession) {
+    const manifest = this.testCases
+      .map(tc => tc.manifest)
+      .reduce(mergeManifests, emptyManifest);
+
+    const snapshotDir = session.assembly.outdir;
+
+    IntegManifestWriter.write(manifest, snapshotDir);
+  }
+}
+
+function mergeManifests(m1: IntegManifest, m2: IntegManifest): IntegManifest {
+  return {
+    version: Manifest.version(),
+    testCases: { ...m1.testCases, ...m2.testCases },
+  };
+}

packages/@aws-cdk/integ-tests/lib/test-case.ts

@@ -1,6 +1,6 @@
-import { IntegManifest, TestCase, TestOptions } from '@aws-cdk/cloud-assembly-schema';
-import { attachCustomSynthesis, ISynthesisSession, Stack } from '@aws-cdk/core';
-import { IntegManifestWriter } from './manifest-writer';
+import { IntegManifest, Manifest, TestCase, TestOptions } from '@aws-cdk/cloud-assembly-schema';
+import { attachCustomSynthesis, Stack, ISynthesisSession } from '@aws-cdk/core';
+import { IntegManifestSynthesizer } from './manifest-synthesizer';
 
 // keep this import separate from other imports to reduce chance for merge conflicts with v2-main
 // eslint-disable-next-line no-duplicate-imports, import/order
@@ -21,18 +21,46 @@ export interface IntegTestCaseProps extends TestOptions {
  * apply to all stacks under this case.
  */
 export class IntegTestCase extends Construct {
-  constructor(scope: Construct, id: string, props: IntegTestCaseProps) {
+  constructor(scope: Construct, private readonly id: string, private readonly props: IntegTestCaseProps) {
     super(scope, id);
+  }
+
+  /**
+   * The integration test manifest for this test case. Manifests are used
+   * by the integration test runner.
+   */
+  get manifest(): IntegManifest {
+    return {
+      version: Manifest.version(),
+      testCases: { [this.id]: toTestCase(this.props) },
+    };
+  }
+}
+
+/**
+ * Integration test properties
+ */
+export interface IntegTestProps {
+  /**
+   * List of test cases that make up this test
+   */
+  readonly testCases: IntegTestCase[];
+}
 
+/**
+ * A collection of test cases. Each test case file should contain exactly one
+ * instance of this class.
+ */
+export class IntegTest extends Construct {
+  constructor(scope: Construct, id: string, private readonly props: IntegTestProps) {
+    super(scope, id);
+  }
+
+  protected onPrepare(): void {
     attachCustomSynthesis(this, {
       onSynthesize: (session: ISynthesisSession) => {
-        const snapshotDir = session.assembly.outdir;
-        const manifest: IntegManifest = {
-          version: '',
-          testCases: { [id]: toTestCase(props) },
-        };
-
-        IntegManifestWriter.write(manifest, snapshotDir);
+        const synthesizer = new IntegManifestSynthesizer(this.props.testCases);
+        synthesizer.synthesize(session);
       },
     });
   }

packages/@aws-cdk/integ-tests/package.json

@@ -70,6 +70,7 @@
   "dependencies": {
     "@aws-cdk/cloud-assembly-schema": "0.0.0",
     "@aws-cdk/core": "0.0.0",
+    "@aws-cdk/cx-api": "0.0.0",
     "constructs": "^3.3.69"
   },
   "repository": {

packages/@aws-cdk/integ-tests/rosetta/default.ts-fixture

@@ -1,5 +1,5 @@
 import * as lambda from '@aws-cdk/aws-lambda';
-import { IntegTestCase } from '@aws-cdk/integ-tests';
+import { IntegTestCase, IntegTest } from '@aws-cdk/integ-tests';
 import {
   App,
   Construct,

packages/@aws-cdk/integ-tests/test/manifest-synthesizer.test.ts

@@ -0,0 +1,45 @@
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { App, Stack } from '@aws-cdk/core';
+import { CloudAssemblyBuilder } from '@aws-cdk/cx-api';
+import { IntegTestCase } from '../lib';
+import { IntegManifestSynthesizer } from '../lib/manifest-synthesizer';
+import { IntegManifestWriter } from '../lib/manifest-writer';
+
+describe(IntegManifestSynthesizer, () => {
+  it('synthesizes a multiple manifests', () => {
+    const write = jest.spyOn(IntegManifestWriter, 'write');
+
+    const app = new App();
+    const stack = new Stack(app, 'stack');
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-test'));
+    const assembly = new CloudAssemblyBuilder(tmpDir);
+
+    const synthesizer = new IntegManifestSynthesizer([
+      new IntegTestCase(stack, 'case1', {
+        stacks: [new Stack(app, 'stack-under-test-1')],
+      }),
+      new IntegTestCase(stack, 'case2', {
+        stacks: [new Stack(app, 'stack-under-test-2')],
+      }),
+    ]);
+
+    synthesizer.synthesize({
+      assembly,
+      outdir: 'asdas',
+    });
+
+    expect(write).toHaveBeenCalledWith({
+      version: '17.0.0',
+      testCases: {
+        case1: {
+          stacks: ['stack-under-test-1'],
+        },
+        case2: {
+          stacks: ['stack-under-test-2'],
+        },
+      },
+    }, tmpDir);
+  });
+});