Adding test converage for plugin loading

Summary: Adds test for the plugin reducer and dispatcher

Reviewed By: jknoxville, passy

Differential Revision: D13082652

fbshipit-source-id: 4af2c7721c4d88abbd332d610ff71d5db78e721c

src/reducers/__tests__/plugins.node.js

@@ -0,0 +1,71 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+import {default as reducer, registerPlugins} from '../plugins';
+import {
+  FlipperBasePlugin,
+  FlipperPlugin,
+  FlipperDevicePlugin,
+} from '../../plugin.js';
+
+const testBasePlugin = class extends FlipperBasePlugin {
+  static id = 'TestPlugin';
+};
+
+const testPlugin = class extends FlipperPlugin {
+  static id = 'TestPlugin';
+};
+
+const testDevicePlugin = class extends FlipperDevicePlugin {
+  static id = 'TestDevicePlugin';
+};
+
+test('add clientPlugin', () => {
+  const res = reducer(
+    {
+      devicePlugins: new Map(),
+      clientPlugins: new Map(),
+    },
+    registerPlugins([testPlugin]),
+  );
+  expect(res.clientPlugins.get(testPlugin.id)).toBe(testPlugin);
+});
+
+test('add devicePlugin', () => {
+  const res = reducer(
+    {
+      devicePlugins: new Map(),
+      clientPlugins: new Map(),
+    },
+    registerPlugins([testDevicePlugin]),
+  );
+  expect(res.devicePlugins.get(testDevicePlugin.id)).toBe(testDevicePlugin);
+});
+
+test('do not add plugin twice', () => {
+  const res = reducer(
+    {
+      devicePlugins: new Map(),
+      clientPlugins: new Map(),
+    },
+    registerPlugins([testPlugin, testPlugin]),
+  );
+  expect(res.clientPlugins.size).toEqual(1);
+});
+
+test('do not add other classes', () => {
+  const res = reducer(
+    {
+      devicePlugins: new Map(),
+      clientPlugins: new Map(),
+    },
+    // $FlowFixMe testing wrong classes on purpose here
+    registerPlugins([testBasePlugin]),
+  );
+  expect(res.devicePlugins.size).toEqual(0);
+  expect(res.devicePlugins.size).toEqual(0);
+});