fix(assertions): cannot use HTTP apis that do not return JSON (#27463)

The `HttpApiCall` handler only supports endpoints that return JSON. Also let it handle regular strings, if the endpoint returns something that is not parseable as JSON.

Fix a type issue in the declared types as well, they never returned a `responseJson` field, just a `body` field.

----

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

Author: rix0rrr

packages/@aws-cdk/integ-tests-alpha/lib/assertions/providers/lambda-handler/http.ts

@@ -15,11 +15,12 @@ export class HttpHandler extends CustomResourceHandler<HttpRequest, HttpResponse
       statusText: response.statusText,
       headers: response.headers.raw(),
     };
+
+    result.body = await response.text();
     try {
-      const jsonResponse = await response.json();
-      result.body = jsonResponse;
+      result.body = JSON.parse(result.body);
     } catch (e) {
-      result.body = {};
+      // Okay
     }
     return {
       apiCallResponse: result,

packages/@aws-cdk/integ-tests-alpha/lib/assertions/providers/lambda-handler/types.ts

@@ -92,9 +92,9 @@ export interface HttpResponse {
   readonly statusText?: string;
 
   /**
-   * The response as JSON
+   * The response, either as parsed JSON or a string literal.
    */
-  readonly responseJson?: { [key: string]: any };
+  readonly body?: any;
 
   /**
    * Headers associated with the response

packages/@aws-cdk/integ-tests-alpha/test/assertions/providers/lambda-handler/http.test.ts

@@ -1,6 +1,6 @@
 import { HttpHandler } from '../../../../lib/assertions/providers/lambda-handler/http';
 import * as fetch from 'node-fetch';
-import { HttpRequest, HttpResponseWrapper } from '../../../../lib';
+import { HttpRequest } from '../../../../lib';
 
 let fetchMock = jest.fn();
 jest.mock('node-fetch');
@@ -34,15 +34,14 @@ beforeEach(() => {
 describe('HttpHandler', () => {
   test('default', async () => {
     // GIVEN
-    const handler = httpHandler() as any;
     const request: HttpRequest = {
       parameters: {
         url: 'url',
       },
     };
 
     // WHEN
-    const response: HttpResponseWrapper = await handler.processEvent(request);
+    const response = await processEvent(request);
 
     // THEN
     expect(response.apiCallResponse).toEqual({
@@ -63,7 +62,6 @@ describe('HttpHandler', () => {
 
   test('with fetch options', async () => {
     // GIVEN
-    const handler = httpHandler() as any;
     const request: HttpRequest = {
       parameters: {
         url: 'url',
@@ -79,7 +77,7 @@ describe('HttpHandler', () => {
     };
 
     // WHEN
-    const response: HttpResponseWrapper = await handler.processEvent(request);
+    const response = await processEvent(request);
 
     // THEN
     expect(response.apiCallResponse).toEqual({
@@ -104,4 +102,34 @@ describe('HttpHandler', () => {
       },
     });
   });
+
+  test('JSON is parsed', async () => {
+    // GIVEN
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ key: 'value' }), { status: 200, statusText: 'OK', ok: true }),
+    );
+
+    // WHEN
+    const response = await processEvent({ parameters: { url: 'x' } });
+
+    // THEN
+    expect(response.apiCallResponse.body).toEqual({ key: 'value' });
+  });
+
+  test('Non-JSON is not parsed', async () => {
+    // GIVEN
+    fetchMock.mockResolvedValue(
+      new Response('this is a string', { status: 200, statusText: 'OK', ok: true }),
+    );
+
+    // WHEN
+    const response = await processEvent({ parameters: { url: 'x' } });
+
+    // THEN
+    expect(response.apiCallResponse.body).toEqual('this is a string');
+  });
 });
+
+function processEvent(request: HttpRequest): ReturnType<HttpHandler['processEvent']> {
+  return (httpHandler() as any).processEvent(request);
+}