Merge pull request #548 from hashicorp/fix-flaky-origin-test

fix: 🐛 migrate IPC to service-based window for reliable testing

ui/desktop/app/services/ipc.js

@@ -1,5 +1,5 @@
 import Service from '@ember/service';
-import { getOwner } from '@ember/application';
+import { inject as service } from '@ember/service';
 import { Promise } from 'rsvp';
 
 /**
@@ -58,7 +58,7 @@ export class IPCRequest {
     this.method = method;
     this.payload = payload;
     this.origin = window?.location?.origin;
-    this.#channel = new MessageChannel();
+    this.#channel = new window.MessageChannel();
     this.#promise = new Promise((resolve, reject) => {
       this.#channel.port1.onmessage = (event) => {
         this.close();
@@ -124,18 +124,9 @@ export class IPCRequest {
  *   }
  */
 export default class IpcService extends Service {
-  // =attributes
+  // =services
 
-  /**
-   * Looks up the window object indirectly.
-   * @type {Window}
-   */
-  get window() {
-    // The Ember way of accessing globals...
-    const document = getOwner(this).lookup('service:-document').documentElement;
-    // defaultView === window, but without using globals directly
-    return document.parentNode.defaultView;
-  }
+  @service('browser/window') window;
 
   // =methods
 

ui/desktop/tests/acceptance/origin-test.js

@@ -19,15 +19,17 @@ import {
   // authenticateSession,
   invalidateSession,
 } from 'ember-simple-auth/test-support';
+import { setupBrowserFakes } from 'ember-browser-services/test-support';
+import WindowMockIPC from '../helpers/window-mock-ipc';
 import config from '../../config/environment';
 
 module('Acceptance | origin', function (hooks) {
   setupApplicationTest(hooks);
+  setupBrowserFakes(hooks, { window: true });
   setupMirage(hooks);
 
   const currentOrigin = window.location.origin;
   let mockIPC;
-  let messageHandler;
 
   const instances = {
     scopes: {
@@ -104,40 +106,12 @@ module('Acceptance | origin', function (hooks) {
     urls.projects = `${urls.scopes.global}/projects`;
     urls.targets = `${urls.projects}/targets`;
 
-    class MockIPC {
-      origin = null;
-
-      invoke(method, payload) {
-        return this[method](payload);
-      }
-
-      getOrigin() {
-        return this.origin;
-      }
-
-      setOrigin(origin) {
-        this.origin = origin;
-        return this.origin;
-      }
-
-      resetOrigin() {}
-    }
-
-    mockIPC = new MockIPC();
-    messageHandler = async function (event) {
-      if (event.origin !== currentOrigin) return;
-      const { method, payload } = event.data;
-      if (method) {
-        const response = await mockIPC.invoke(method, payload);
-        event.ports[0].postMessage(response);
-      }
-    };
-
-    window.addEventListener('message', messageHandler);
+    // Mock the postMessage interface used by IPC.
+    this.owner.register('service:browser/window', WindowMockIPC);
+    mockIPC = this.owner.lookup('service:browser/window').mockIPC;
   });
 
   hooks.afterEach(function () {
-    window.removeEventListener('message', messageHandler);
     sinon.restore();
   });
 

ui/desktop/tests/helpers/window-mock-ipc.js

@@ -0,0 +1,66 @@
+import Service from '@ember/service';
+
+class MockIPC {
+  origin = null;
+
+  invoke(method, payload) {
+    return this[method](payload);
+  }
+
+  getOrigin() {
+    return this.origin;
+  }
+
+  setOrigin(origin) {
+    this.origin = origin;
+    return this.origin;
+  }
+
+  resetOrigin() {}
+}
+
+/**
+ * Mock window service with support for simplified postMessage and
+ * MessageChannel APIs.  This mock implements just enough functionality
+ * to support the IPC mechanism.
+ *
+ * This mock is necessary to guarantee synchronous and deterministic
+ * operation.  The window's own API is evented and asychronous, which
+ * cannot be relied on for testing purposes.
+ *
+ * @todo refactor mock postMessage and MessageChannel for reusability
+ *       outside of tests
+ */
+export default class extends Service {
+  // =attributes
+
+  mockIPC = new MockIPC();
+
+  MessageChannel = class MessageChannel {
+    constructor() {
+      this.port1.postMessage = this.port1.postMessage.bind(this);
+      this.port2.postMessage = this.port2.postMessage.bind(this);
+    }
+    port1 = {
+      postMessage() {},
+      close() {},
+    };
+    port2 = {
+      postMessage(data) {
+        this.port1.onmessage({ data });
+      },
+      close() {},
+    };
+  };
+
+  // =methods
+
+  postMessage(data, origin, ports) {
+    if (origin !== window.location.origin) return;
+    const { method, payload } = data;
+    if (method) {
+      const response = this.mockIPC.invoke(method, payload);
+      ports[0].postMessage(response);
+    }
+  }
+}

ui/desktop/tests/unit/services/ipc-test.js

@@ -6,6 +6,23 @@ import sinon from 'sinon';
 module('Unit | Service | ipc', function (hooks) {
   setupTest(hooks);
 
+  class MessageChannelMock {
+    constructor() {
+      this.port1.postMessage = this.port1.postMessage.bind(this);
+      this.port2.postMessage = this.port2.postMessage.bind(this);
+    }
+    port1 = {
+      postMessage() {},
+      close() {},
+    };
+    port2 = {
+      postMessage(data) {
+        this.port1.onmessage({ data });
+      },
+      close() {},
+    };
+  }
+
   hooks.beforeEach(() => {
     // IPC requests talk to the main process indirectly via window.postMessage
     // proxy layer (mediated by preload.js).
@@ -31,6 +48,7 @@ module('Unit | Service | ipc', function (hooks) {
         assert.equal(request.method, 'hello');
         assert.equal(request.payload, 'world');
       },
+      MessageChannel: MessageChannelMock,
     };
     new IPCRequest('hello', 'world', myWindow);
   });
@@ -45,6 +63,7 @@ module('Unit | Service | ipc', function (hooks) {
           test: 42,
         });
       },
+      MessageChannel: MessageChannelMock,
     };
     const request = new IPCRequest('hello', 'world', myWindow);
     const response = await request;
@@ -65,6 +84,7 @@ module('Unit | Service | ipc', function (hooks) {
         // Post back an error on the response port
         port.postMessage(new Error(stringifiedPayload));
       },
+      MessageChannel: MessageChannelMock,
     };
     try {
       await new IPCRequest('hello', 'world', myWindow);