unit tests impl.

Author: Elad Gil

__mocks__/RNBackgroundDownload.js

@@ -1,6 +1,67 @@
 import { NativeModules } from 'react-native';
 
+const listeners = {};
+
+// states:
+// 0 - Running
+// 1 - Suspended / Paused
+// 2 - Cancelled / Failed
+// 3 - Completed (not necessarily successfully)
+
 NativeModules.RNBackgroundDownload = {
     download: jest.fn(),
-    addListener: jest.fn()
+    pauseTask: jest.fn(),
+    resumeTask: jest.fn(),
+    stopTask: jest.fn(),
+    TaskRunning: 0,
+    TaskSuspended: 1,
+    TaskCanceling: 2,
+    TaskCompleted: 3,
+    checkForExistingDownloads: jest.fn().mockImplementation(() => {
+        foundDownloads = [
+            {
+                id: 'taskRunning',
+                state: NativeModules.RNBackgroundDownload.TaskRunning,
+                percent: 0.5,
+                bytesWritten: 50,
+                totalBytes: 100
+            },
+            {
+                id: 'taskPaused',
+                state: NativeModules.RNBackgroundDownload.TaskSuspended,
+                percent: 0.7,
+                bytesWritten: 70,
+                totalBytes: 100
+            },
+            {
+                id: 'taskCancelled',
+                percent: 0.9,
+                state: NativeModules.RNBackgroundDownload.TaskCanceling,
+                bytesWritten: 90,
+                totalBytes: 100
+            },
+            {
+                id: 'taskCompletedExplicit',
+                state: NativeModules.RNBackgroundDownload.TaskCompleted,
+                percent: 1,
+                bytesWritten: 100,
+                totalBytes: 100
+            },
+            {
+                id: 'taskCompletedImplicit',
+                state: NativeModules.RNBackgroundDownload.TaskCompleted,
+                percent: 1,
+                bytesWritten: 100,
+                totalBytes: 100
+            },
+            {
+                id: 'taskFailed',
+                state: NativeModules.RNBackgroundDownload.TaskCompleted,
+                percent: 0.9,
+                bytesWritten: 90,
+                totalBytes: 100
+            }
+        ]
+        return Promise.resolve(foundDownloads);
+    })
 };

__tests__/mainTest.js

@@ -1,10 +1,149 @@
+jest.mock('NativeEventEmitter', () => {
+    return class NativeEventEmitter {
+        static listeners = {};
+
+        addListener(channel, cb) {
+            NativeEventEmitter.listeners[channel] = cb;
+        }
+    };
+});
+
 import RNBackgroundDownload from '../index';
 import DownloadTask from '../lib/downloadTask';
+import { NativeEventEmitter, NativeModules } from 'react-native';
+
+const RNBackgroundDownloadNative = NativeModules.RNBackgroundDownload;
 
-test('download should return a downloadTask', () => {
-    expect(RNBackgroundDownload.download({
+let downloadTask;
+
+test('download function', () => {
+    downloadTask = RNBackgroundDownload.download({
         id: 'test',
         url: 'test',
         destination: 'test'
-    })).toBeInstanceOf(DownloadTask);
-});
+    });
+    expect(downloadTask).toBeInstanceOf(DownloadTask);
+    expect(RNBackgroundDownloadNative.download).toHaveBeenCalled();
+});
+
+test('begin event', () => {
+    return new Promise(resolve => {
+        const beginDT = RNBackgroundDownload.download({
+            id: 'testBegin',
+            url: 'test',
+            destination: 'test'
+        }).begin((expectedBytes) => {
+            expect(expectedBytes).toBe(9001);
+            expect(beginDT.state).toBe('DOWNLOADING');
+            resolve();
+        });
+        NativeEventEmitter.listeners.downloadBegin({
+            id: 'testBegin',
+            expctedBytes: 9001
+        });
+    });
+});
+
+test('progress event', () => {
+    return new Promise(resolve => {
+        RNBackgroundDownload.download({
+            id: 'testProgress',
+            url: 'test',
+            destination: 'test'
+        }).progress((percent, bytesWritten, totalBytes) => {
+            expect(percent).toBeCloseTo(0.7);
+            expect(bytesWritten).toBe(100);
+            expect(totalBytes).toBe(200);
+            resolve();
+        });
+        NativeEventEmitter.listeners.downloadProgress([{
+            id: 'testProgress',
+            percent: 0.7,
+            written: 100,
+            total: 200
+        }]);
+    });
+});
+
+test('done event', () => {
+    return new Promise(resolve => {
+        const doneDT = RNBackgroundDownload.download({
+            id: 'testDone',
+            url: 'test',
+            destination: 'test'
+        }).done(() => {
+            expect(doneDT.state).toBe('DONE');
+            resolve();
+        });
+        NativeEventEmitter.listeners.downloadComplete({
+            id: 'testDone'
+        });
+    });
+});
+
+test('fail event', () => {
+    return new Promise(resolve => {
+        const failDT = RNBackgroundDownload.download({
+            id: 'testFail',
+            url: 'test',
+            destination: 'test'
+        }).error((error) => {
+            expect(error).toBeInstanceOf(Error);
+            expect(failDT.state).toBe('FAILED');
+            resolve();
+        });
+        NativeEventEmitter.listeners.downloadFailed({
+            id: 'testFail',
+            error: new Error('test')
+        });
+    });
+});
+
+test('pause', () => {
+    const pauseDT = RNBackgroundDownload.download({
+        id: 'testPause',
+        url: 'test',
+        destination: 'test'
+    });
+
+    pauseDT.pause();
+    expect(pauseDT.state).toBe('PAUSED');
+    expect(RNBackgroundDownloadNative.pauseTask).toHaveBeenCalled();
+});
+
+test('resume', () => {
+    const resumeDT = RNBackgroundDownload.download({
+        id: 'testResume',
+        url: 'test',
+        destination: 'test'
+    });
+
+    resumeDT.resume();
+    expect(resumeDT.state).toBe('DOWNLOADING');
+    expect(RNBackgroundDownloadNative.resumeTask).toHaveBeenCalled();
+});
+
+test('stop', () => {
+    const stopDT = RNBackgroundDownload.download({
+        id: 'testStop',
+        url: 'test',
+        destination: 'test'
+    });
+
+    stopDT.stop();
+    expect(stopDT.state).toBe('STOPPED');
+    expect(RNBackgroundDownloadNative.stopTask).toHaveBeenCalled();
+});
+
+test('checkForExistingDownloads', () => {
+    return RNBackgroundDownload.checkForExistingDownloads()
+        .then(foundDownloads => {
+            expect(RNBackgroundDownloadNative.checkForExistingDownloads).toHaveBeenCalled();
+            expect(foundDownloads.length).toBe(4);
+            foundDownloads.forEach(foundDownload => {
+                expect(foundDownload).toBeInstanceOf(DownloadTask);
+                expect(foundDownload.state).not.toBe('FAILED');
+                expect(foundDownload.state).not.toBe('STOPPED');
+            });
+        })
+})

package.json

@@ -20,6 +20,9 @@
   },
   "jest": {
     "preset": "react-native",
-    "setupFiles": ["./__mocks__/RNBackgroundDownload.js"]
+    "setupFiles": [
+      "./__mocks__/RNBackgroundDownload.js",
+      "./node_modules/react-native/Libraries/EventEmitter/__mocks__/NativeEventEmitter.js"
+    ]
   }
 }