Jest Tests

.circleci/config.yml

@@ -73,9 +73,9 @@ aliases:
   name: Flow Checks
   command: yarn test:flow
 
-- &javascript
-  name: Javascript Tests
-  command: yarn test:js
+- &jest
+  name: Jest Unit Tests
+  command: yarn test:jest
 
 # -------------------------
 #          JOBS
@@ -110,12 +110,12 @@ jobs:
         at: ~/react-native-netinfo
     - run: *flow
 
-  javascript:
+  jest:
     <<: *linux_defaults
     steps:
     - attach_workspace:
         at: ~/react-native-netinfo
-    - run: *javascript
+    - run: *jest
 
   android-compile:
     <<: *android_defaults
@@ -172,7 +172,7 @@ workflows:
     - flow:
         requires:
         - linux-checkout
-    - javascript:
+    - jest:
         requires:
         - linux-checkout
     - android-compile:

.gitignore

@@ -46,3 +46,6 @@ buck-out/
 
 # Editor config
 .vscode
+
+# Outputs
+coverage

jest.setup.js

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+/* eslint-env jest */
+
+import {NativeModules} from 'react-native';
+
+// Mock the RNCNetInfo native module to allow us to unit test the JavaScript code
+NativeModules.RNCNetInfo = {
+  getCurrentConnectivity: jest.fn(),
+  isConnectionMetered: jest.fn(),
+  addListener: jest.fn(),
+  removeListeners: jest.fn(),
+};
+
+// Reset the mocks before each test
+global.beforeEach(() => {
+  jest.resetAllMocks();
+});

js/__tests__/eventListenerCallbacks.js

@@ -0,0 +1,111 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+/* eslint-env jest */
+
+import {NativeModules} from 'react-native';
+import NetInfo from '../index';
+import {NetInfoEventEmitter} from '../nativeInterface';
+
+describe('react-native-netinfo', () => {
+  describe('Event listener callbacks', () => {
+    it('should call the listener when the native event is emmitted', () => {
+      const listener = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener);
+
+      const expectedConnectionType = 'cellular';
+      const expectedEffectiveConnectionType = '3g';
+
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: expectedConnectionType,
+        effectiveConnectionType: expectedEffectiveConnectionType,
+      });
+
+      expect(listener).toBeCalledWith({
+        type: expectedConnectionType,
+        effectiveType: expectedEffectiveConnectionType,
+      });
+    });
+
+    it('should call the listener multiple times when multiple native events are emmitted', () => {
+      const listener = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener);
+
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: 'cellular',
+        effectiveConnectionType: '3g',
+      });
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: 'wifi',
+        effectiveConnectionType: 'unknown',
+      });
+
+      expect(listener).toBeCalledTimes(2);
+    });
+
+    it('should call all listeners when the native event is emmitted', () => {
+      const listener1 = jest.fn();
+      const listener2 = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener1);
+      NetInfo.addEventListener('connectionChange', listener2);
+
+      const expectedConnectionType = 'cellular';
+      const expectedEffectiveConnectionType = '3g';
+
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: expectedConnectionType,
+        effectiveConnectionType: expectedEffectiveConnectionType,
+      });
+
+      const expectedResults = {
+        type: expectedConnectionType,
+        effectiveType: expectedEffectiveConnectionType,
+      };
+
+      expect(listener1).toBeCalledWith(expectedResults);
+      expect(listener2).toBeCalledWith(expectedResults);
+    });
+
+    it('should not call the listener after being removed', () => {
+      const listener = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener);
+      NetInfo.removeEventListener('connectionChange', listener);
+
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: 'cellular',
+        effectiveConnectionType: '3g',
+      });
+
+      expect(listener).not.toBeCalled();
+    });
+
+    it('should call the remaining listeners when one has been removed', () => {
+      const listener1 = jest.fn();
+      const listener2 = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener1);
+      NetInfo.addEventListener('connectionChange', listener2);
+
+      NetInfo.removeEventListener('connectionChange', listener1);
+
+      const expectedConnectionType = 'cellular';
+      const expectedEffectiveConnectionType = '3g';
+
+      NetInfoEventEmitter.emit(NetInfo.Events.NetworkStatusDidChange, {
+        connectionType: expectedConnectionType,
+        effectiveConnectionType: expectedEffectiveConnectionType,
+      });
+
+      expect(listener1).not.toBeCalled();
+      expect(listener2).toBeCalledWith({
+        type: expectedConnectionType,
+        effectiveType: expectedEffectiveConnectionType,
+      });
+    });
+  });
+});

js/__tests__/eventListenerManagement.js

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+/* eslint-env jest */
+
+import {NativeModules} from 'react-native';
+import NetInfo from '../index';
+import {NetInfoEventEmitter} from '../nativeInterface';
+
+describe('react-native-netinfo', () => {
+  describe('Event listener management', () => {
+    it('should add the listener to the native module when passing the correct event name', () => {
+      NetInfo.addEventListener('connectionChange', jest.fn());
+      expect(NativeModules.RNCNetInfo.addListener).toBeCalledWith(
+        NetInfo.Events.NetworkStatusDidChange,
+      );
+    });
+
+    it('should do nothing when passing the wrong event name', () => {
+      // $FlowExpectedError We are testing passing in the wrong name
+      NetInfo.addEventListener('WRONGNAME', jest.fn());
+      expect(NativeModules.RNCNetInfo.addListener).not.toBeCalled();
+    });
+
+    it('should not error when calling remove on an invalid subscription', () => {
+      // $FlowExpectedError We are testing passing in the wrong name
+      const subscription = NetInfo.addEventListener('WRONGNAME', jest.fn());
+      subscription.remove();
+      expect(NativeModules.RNCNetInfo.addListener).not.toBeCalled();
+    });
+
+    it('should remove the listener from the native module when calling removeEventListener', () => {
+      const listener = jest.fn();
+      NetInfo.addEventListener('connectionChange', listener);
+      NetInfo.removeEventListener('connectionChange', listener);
+      expect(NativeModules.RNCNetInfo.removeListeners).toBeCalled();
+    });
+
+    it('should not call the native module if asked to remove a listener which was never added', () => {
+      NetInfo.removeEventListener('connectionChange', jest.fn());
+      expect(NativeModules.RNCNetInfo.removeListeners).not.toBeCalled();
+    });
+
+    it('should remove the listener from the native module when calling remove on the returned subscription', () => {
+      const listener = jest.fn();
+      const subscription = NetInfo.addEventListener(
+        'connectionChange',
+        listener,
+      );
+      subscription.remove();
+      expect(NativeModules.RNCNetInfo.removeListeners).toBeCalled();
+    });
+  });
+});

js/__tests__/getConnectionInfo.js

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+/* eslint-env jest */
+
+import NetInfo from '../index';
+import {RNCNetInfo} from '../nativeInterface';
+
+describe('react-native-netinfo', () => {
+  describe('getConnectionInfo', () => {
+    it('should pass on the responses when the library promise returns', () => {
+      const expectedConnectionType = 'cellular';
+      const expectedEffectiveConnectionType = '3g';
+
+      RNCNetInfo.getCurrentConnectivity.mockResolvedValue({
+        connectionType: expectedConnectionType,
+        effectiveConnectionType: expectedEffectiveConnectionType,
+      });
+
+      return expect(NetInfo.getConnectionInfo()).resolves.toEqual({
+        type: expectedConnectionType,
+        effectiveType: expectedEffectiveConnectionType,
+      });
+    });
+
+    it('should pass on errors through the promise chain', () => {
+      const expectedError = new Error('A test error');
+
+      RNCNetInfo.getCurrentConnectivity.mockRejectedValue(expectedError);
+
+      return expect(NetInfo.getConnectionInfo()).rejects.toBe(expectedError);
+    });
+  });
+});