Android - 測試我的應用程序時，如何模擬缺相機？

Question

我想檢查一下，當它運行的設備沒有攝像頭時，我的應用程序會顯示一條錯誤消息。我嘗試傳遞一個模擬上下文，但當我試圖模擬CameraManager類時，mockito給出了一個錯誤，因爲它聲明爲final。當然，android有一個簡單的解決方案呢？這是我的嘗試：

public class CreateNewIdentityActivityUnitTest extends ActivityUnitTestCase<CreateNewIdentityActivity> { 
    public CreateNewIdentityActivityUnitTest() { 
     super(CreateNewIdentityActivity.class); 
    } 

    public void testErrorMessageDisplayedWhenNoCamerasExist() throws Exception { 
     // Create the mock cameramanager 
     // THIS LINE FAILS BECAUSE CAMERAMANAGER IS FINAL 
     CameraManager mockCameraManager = mock(CameraManager.class); 
     String[] cameraIdList = {}; 
     when(mockCameraManager.getCameraIdList()).thenReturn(cameraIdList); 

     // Create the mock context 
     Context mockContext = mock(Context.class); 
     when(mockContext.getSystemService(Context.CAMERA_SERVICE)).thenReturn(mockCameraManager); 

     // Start the activity 
     Intent intent = new Intent(mockContext, CreateNewIdentityActivity.class); 
     Activity activity = startActivity(intent, null, null); 

     // Verify that the error message was made visible 
     TextView errorTextView = (TextView)activity.findViewById(R.id.ErrorTextView); 
     assertNotNull(errorTextView); 
     assertEquals(View.VISIBLE, errorTextView.getVisibility()); 
    } 
} 

Answer 1

不幸的是，你不能嘲笑final類。

有是幾個選項/黑客：

• 嘗試添加Robolectric庫，並編寫測試與它的相關CameraManager成一個單獨的類ShadowCamera
• 移動邏輯和活動注入它。然後在Test項目中，您可以重寫此注入。

• 漂亮類似的想法 - 建立一個interface OnCameraManagerInterface

  public interface OnCameraManagerInterface { 
      String[] getListOfCameras() throws CameraAccessException; 
  } 
  

  然後在活動實現：

  public class CreateNewIdentityActivity extends AppCompatActivity 
       implements OnCameraManagerInterface { 
      ....... 
      @TargetApi(Build.VERSION_CODES.LOLLIPOP) 
      @Override 
      public String[] getListOfCameras() throws CameraAccessException { 
       return ((CameraManager)getSystemService(Context.CAMERA_SERVICE)). 
          getCameraIdList(); 
      } 
  } 
  

  並在代碼，在那裏你檢查相機的存在 - 撥打：if (getListOfCameras().length == 0) {}

  現在，添加新的TestCreateNewIdentityActivity以覆蓋您的CreateNewIdentityActivity：

  public class TestCreateNewIdentityActivity extends CreateNewIdentityActivity { 
      @Override 
      public String[] getListOfCameras() throws CameraAccessException { 
       return new String[0]; 
      } 
  } 
  

  在清單：

  <activity android:name=".TestCreateNewIdentityActivity" 
       android:theme="@style/AppTheme.NoActionBar"/> 
  

  和測試看起來像：

  public class CreateNewIdentityActivityUnitTest extends ActivityUnitTestCase<TestCreateNewIdentityActivity> { 
      public CreateNewIdentityActivityUnitTest() { 
       super(TestCreateNewIdentityActivity.class); 
      } 
  
      public void testErrorMessageDisplayedWhenNoCamerasExist() throws Exception { 
       // Verify that the error message was made visible 
       TextView errorTextView = (TextView)getActivity().findViewById(R.id.ErrorTextView); 
       assertNotNull(errorTextView); 
       assertEquals(View.VISIBLE, errorTextView.getVisibility()); 
      } 
  } 
  

  我敢肯定，它甚至是可行的不添加測試活動進入主源代碼和體現（以保持它在androidTest，雖然我沒看）

• 混合變種沒有創建新的活動：

  public class ActivityCameraManager { 
  
      private boolean isTest = false; 
      private CameraManager cameraManager; 
  
      public ActivityCameraManager(CameraManager cameraManager) { 
       this.cameraManager = cameraManager; 
      } 
  
      @TargetApi(Build.VERSION_CODES.LOLLIPOP) 
      public String[] getListOfCameras() throws CameraAccessException { 
       if (isTest) { 
        return new String[0]; 
       } 
  
       return cameraManager.getCameraIdList(); 
      } 
  
      public void setTestMode() { 
       isTest = true; 
      } 
  } 
  

  那麼你的活動是要去樣子：

  public class MainActivity extends AppCompatActivity { 
  
      ActivityCameraManager activityCameraManager; 
  
      @Override 
      protected void onCreate(Bundle savedInstanceState) { 
       super.onCreate(savedInstanceState); 
       ... 
       activityCameraManager = new ActivityCameraManager((CameraManager) getSystemService(Context.CAMERA_SERVICE)); 
      } 
  
      public void setActivityCameraManagerForTest() { 
       activityCameraManager.setTestMode(); 
      } 
  } 
  

  而且在測試只需撥打getActivity().setActivityCameraManagerForTest();

我希望，它有助於

Answer 2

答案是晚，但這裏Android的模擬相機示例。

你可以從視頻文件

textureVideoInputSource = new VideoFileInputSource(this, "mock_input_video.mp4"); 

設置VideoFileInputSource到模擬攝像機或您可以爲視頻流硬件攝像頭。

textureVideoInputSource = new CameraTextureVideoInputSource(this); 

你可以參考這裏的答案。 https://stackoverflow.com/a/38456189/1053097