refactor: move mock IPC to initializer

ui/desktop/app/initializers/ipc.js

@@ -0,0 +1,51 @@
+import Ember from 'ember';
+import config from '../config/environment';
+
+/**
+ * We strive to make this application runnable in a regular web browser, since
+ * it is a convenient environment for development and testing.  But only an
+ * Electron environment has true IPC.  Outside of Electron, we mock the handling
+ * of the message-based IPC requests originating from the
+ * renderer (the Ember app).
+ */
+class MockIPC {
+  async invoke(method, payload) {
+    console.log('MockIPC:', method, payload);
+    return await this[method](payload);
+  }
+
+  origin = null;
+
+  getOrigin() {
+    return this.origin;
+  }
+
+  setOrigin(origin) {
+    this.origin = origin;
+    return this.origin;
+  }
+}
+
+/**
+ * Establishes a mock IPC handler, which mimics the behavior of the Electron
+ * main process, and routes messages to it in a way similar to our
+ * preload.js script.
+ *
+ * Initializes mock IPC only in a non-Electron non-testing context.
+ */
+export function initialize() {
+  if (!config.isElectron && !Ember.testing) {
+    const mockIPC = new MockIPC();
+    window.addEventListener('message', async function (event) {
+      if (event.origin !== window.location.origin) return;
+      const { method, payload } = event.data;
+      if (method) {
+        const response =
+          await mockIPC.invoke(method, payload);
+        event.ports[0].postMessage(response);
+      }
+    });
+  }
+}
+
+export default { initialize };

ui/desktop/mirage/config.js

@@ -6,38 +6,6 @@ import { Response } from 'miragejs';
 
 export default function() {
 
-  if (!config.isElectron && !Ember.testing) {
-    class MockIPC {
-      invoke(method, payload) {
-        console.log('MockIPC:', method, payload);
-        return this[method](payload);
-      }
-
-      origin = null;
-
-      getOrigin() {
-        return this.origin;
-      }
-
-      setOrigin(origin) {
-        this.origin = origin;
-        return this.origin;
-      }
-    }
-
-    const mockIPC = new MockIPC();
-
-    window.addEventListener('message', async function (event) {
-      if (event.origin !== window.location.origin) return;
-      const { method, payload } = event.data;
-      if (method) {
-        const response =
-          await mockIPC.invoke(method, payload);
-        event.ports[0].postMessage(response);
-      }
-    });
-  }
-
   // make this `http://localhost:8080`, for example, if your API is on a different server
   // this.urlPrefix = '';
   // make this `/api`, for example, if your API is namespaced

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

@@ -0,0 +1,28 @@
+import Application from '@ember/application';
+
+import { initialize } from 'desktop/initializers/ipc';
+import { module, test } from 'qunit';
+import { run } from '@ember/runloop';
+
+module('Unit | Initializer | ipc', function(hooks) {
+  hooks.beforeEach(function() {
+    this.TestApplication = Application.extend();
+    this.TestApplication.initializer({
+      name: 'initializer under test',
+      initialize
+    });
+
+    this.application = this.TestApplication.create({ autoboot: false });
+  });
+
+  hooks.afterEach(function() {
+    run(this.application, 'destroy');
+  });
+
+  // TODO: Replace this with your real tests.
+  test('it works', async function(assert) {
+    await this.application.boot();
+
+    assert.ok(true);
+  });
+});