Add tests for Menu screen

src/screens/Menu.js

@@ -12,7 +12,7 @@ import {
 import Settings from '../components/Settings';
 import Debuggers from '../components/Debuggers';
 
-class Menu extends React.Component {
+export class Menu extends React.Component {
   static navigationOptions = {
     title: 'Settings',
   };
@@ -44,7 +44,7 @@ const mapStateToProps = state => ({
   currentPasscode: getCurrentPasscode(state),
 });
 
-const mapDispatchToProps = dispatch => ({
+export const mapDispatchToProps = dispatch => ({
   handleTogglePasscodeRequirement(currentPasscode, requirePasscode) {
     if (!currentPasscode && !requirePasscode) {
       Alert.alert(

src/screens/Menu.test.js

@@ -0,0 +1,58 @@
+import React from 'react';
+import { Alert } from 'react-native';
+
+import { Menu, mapDispatchToProps as dispatchProps } from './Menu';
+import {
+  TOGGLE_PASSCODE_REQUIREMENT,
+  RESET_PASSCODE_SETTINGS,
+} from '../redux/modules/settings';
+
+describe('Menu screen test', () => {
+  it('should render as expected', () => {
+    const wrapper = shallow(<Menu />);
+    expect(wrapper).toMatchSnapshot();
+  });
+
+  describe('mapDispatchToProps test', () => {
+    beforeEach(() => {
+      jest.resetModules();
+      jest.mock('Alert', () => ({
+        alert: jest.fn(),
+      }));
+    });
+
+    describe('handleTogglePasscodeRequirement test', () => {
+      it('should not activate passscode requirement if user no passcode set yet', () => {
+        const dispatchMock = jest.fn();
+        const props = dispatchProps(dispatchMock);
+        props.handleTogglePasscodeRequirement(null, false);
+        expect(Alert.alert.mock.calls.length).toBe(1);
+        expect(dispatchMock.mock.calls.length).toBe(0);
+      });
+
+      it('should activate passcode requirement if user has set a passcode', () => {
+        const dispatchMock = jest.fn();
+        const props = dispatchProps(dispatchMock);
+        props.handleTogglePasscodeRequirement('HASH', true);
+        expect(Alert.alert.mock.calls.length).toBe(0);
+        expect(dispatchMock.mock.calls.length).toBe(1);
+        expect(dispatchMock.mock.calls[0]).toEqual([
+          { type: TOGGLE_PASSCODE_REQUIREMENT },
+        ]);
+      });
+    });
+
+    describe('onPasscodeSettingsReset test', () => {
+      it('should dispatch reset action if user presses OK', () => {
+        const dispatchMock = jest.fn();
+        const props = dispatchProps(dispatchMock);
+        props.onPasscodeSettingsReset();
+        expect(Alert.alert.mock.calls.length).toBe(1);
+        Alert.alert.mock.calls[0][2][1].onPress();
+        expect(dispatchMock.mock.calls[0]).toEqual([
+          { type: RESET_PASSCODE_SETTINGS },
+        ]);
+      });
+    });
+  });
+});

src/screens/__snapshots__/Menu.test.js.snap

@@ -0,0 +1,10 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Menu screen test should render as expected 1`] = `
+<ScrollView>
+  <Settings
+    handleSetPasscode={[Function]}
+  />
+  <Debuggers />
+</ScrollView>
+`;