Plugin name list

Summary:
Adds an argument to the headless Flipper to print the list of available plugins. Added `--list-plugins`.

Currently the startFlipper function is not scalable enough to add new arguments and its implementation. I am planning to tackle this with the list of Actions which will be closure. So adding a new argument with its implementation will be just appending a closure at the correct location in an array. Will work on that in the later diff stacked on the current one.

Reviewed By: jknoxville

Differential Revision: D15789778

fbshipit-source-id: 91ba472617d593c3490bb932590a06d83597cba7

src/utils/__tests__/pluginUtils.node.js

@@ -0,0 +1,62 @@
+/**
+ * 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 {getActivePluginNames} from '../pluginUtils';
+import type {State as PluginsState} from '../../reducers/plugins.js';
+import type {PluginDefinition} from '../../dispatcher/plugins';
+
+function mockPluginState(
+  gatekeepedPlugins: Array<PluginDefinition>,
+  disabledPlugins: Array<PluginDefinition>,
+  failedPlugins: Array<[PluginDefinition, string]>,
+): PluginsState {
+  return {
+    devicePlugins: new Map([
+      //$FlowFixMe: Class instance won't be used in the test
+      ['DevicePlugin1', undefined],
+      //$FlowFixMe: Class instance won't be used in the test
+      ['DevicePlugin2', undefined],
+    ]),
+    clientPlugins: new Map([
+      //$FlowFixMe: Class instance won't be used in the test
+      ['ClientPlugin1', undefined],
+      //$FlowFixMe: Class instance won't be used in the test
+      ['ClientPlugin2', undefined],
+    ]),
+    gatekeepedPlugins,
+    disabledPlugins,
+    failedPlugins,
+  };
+}
+
+function mockPluginDefinition(name: string): PluginDefinition {
+  return {
+    name,
+    out: 'out',
+  };
+}
+
+test('getActivePluginNames with the plugins getting excluded', () => {
+  let state = mockPluginState(
+    [mockPluginDefinition('DevicePlugin1')],
+    [mockPluginDefinition('ClientPlugin1')],
+    [[mockPluginDefinition('DevicePlugin2'), 'DevicePlugin2']],
+  );
+  let list = getActivePluginNames(state);
+  expect(list).toEqual(['ClientPlugin2']);
+});
+
+test('getActivePluginNames with the no plugins getting excluded', () => {
+  let state = mockPluginState([], [], []);
+  let list = getActivePluginNames(state);
+  expect(list).toEqual([
+    'ClientPlugin1',
+    'ClientPlugin2',
+    'DevicePlugin1',
+    'DevicePlugin2',
+  ]);
+});