Add tests for the scaffolder eventstream frontend client

Signed-off-by: Dominik Henneke <dominik.henneke@sda-se.com>

plugins/scaffolder/package.json

@@ -77,6 +77,7 @@
     "@types/jest": "^26.0.7",
     "@types/node": "^14.14.32",
     "cross-fetch": "^3.0.6",
+    "event-source-polyfill": "^1.0.25",
     "msw": "^0.35.0"
   },
   "files": [

plugins/scaffolder/src/api.test.ts

@@ -14,12 +14,18 @@
  * limitations under the License.
  */
 
+import { ConfigReader } from '@backstage/core-app-api';
 import { ScmIntegrations } from '@backstage/integration';
 import { ScaffolderClient } from './api';
-import { ConfigReader } from '@backstage/core-app-api';
+
+const MockedEventSource = global.EventSource as jest.MockedClass<
+  typeof EventSource
+>;
 
 describe('api', () => {
-  const discoveryApi = {} as any;
+  const mockBaseUrl = 'http://backstage/api';
+
+  const discoveryApi = { getBaseUrl: async () => mockBaseUrl };
   const identityApi = {} as any;
   const scmIntegrationsApi = ScmIntegrations.fromConfig(
     new ConfigReader({
@@ -32,10 +38,14 @@ describe('api', () => {
       },
     }),
   );
-  const apiClient = new ScaffolderClient({
-    scmIntegrationsApi,
-    discoveryApi,
-    identityApi,
+
+  let apiClient: ScaffolderClient;
+  beforeEach(() => {
+    apiClient = new ScaffolderClient({
+      scmIntegrationsApi,
+      discoveryApi,
+      identityApi,
+    });
   });
 
   it('should return default and custom integrations', async () => {
@@ -51,4 +61,58 @@ describe('api', () => {
       expect(allowedHosts).toContain(integration.host),
     );
   });
+
+  describe('streamEvents', () => {
+    describe('eventsource', () => {
+      it('should work', async () => {
+        MockedEventSource.prototype.addEventListener.mockImplementation(
+          (type, fn) => {
+            if (typeof fn !== 'function') {
+              return;
+            }
+
+            if (type === 'log') {
+              fn({
+                data: '{"id":1,"taskId":"a-random-id","type":"log","createdAt":"","body":{"message":"My log message"}}',
+              } as any);
+            } else if (type === 'completion') {
+              fn({
+                data: '{"id":2,"taskId":"a-random-id","type":"completion","createdAt":"","body":{"message":"Finished!"}}',
+              } as any);
+            }
+          },
+        );
+
+        const next = jest.fn();
+
+        await new Promise<void>(complete => {
+          apiClient
+            .streamLogs({ taskId: 'a-random-task-id' })
+            .subscribe({ next, complete });
+        });
+
+        expect(MockedEventSource).toBeCalledWith(
+          'http://backstage/api/v2/tasks/a-random-task-id/eventstream',
+          { withCredentials: true },
+        );
+        expect(MockedEventSource.prototype.close).toBeCalled();
+
+        expect(next).toBeCalledTimes(2);
+        expect(next).toBeCalledWith({
+          id: 1,
+          taskId: 'a-random-id',
+          type: 'log',
+          createdAt: '',
+          body: { message: 'My log message' },
+        });
+        expect(next).toBeCalledWith({
+          id: 2,
+          taskId: 'a-random-id',
+          type: 'completion',
+          createdAt: '',
+          body: { message: 'Finished!' },
+        });
+      });
+    });
+  });
 });

plugins/scaffolder/src/setupTests.ts

@@ -15,3 +15,6 @@
  */
 
 import '@testing-library/jest-dom';
+
+const { EventSourcePolyfill } = jest.requireMock('event-source-polyfill');
+global.EventSource = EventSourcePolyfill;