Android Espresso - 測試ListView行

Question

我目前正在嘗試使用Espresso在Android上測試ListView，並使用自定義ArrayAdapter。 下面是測試：

final AssociationsListActivity listActivity = getActivity(); 

    final Association association1 = new Association(ASSOCIATION_NAMES[0], ASSOCIATION_DESCRIPTIONS[0]); 
    final Association association2 = new Association(ASSOCIATION_NAMES[1], ASSOCIATION_DESCRIPTIONS[1]); 
    final Association association3 = new Association(ASSOCIATION_NAMES[2], ASSOCIATION_DESCRIPTIONS[2]); 

    listActivity.addAssociation(association1); 
    listActivity.addAssociation(association2); 
    listActivity.addAssociation(association3); 

    assertTrue(listActivity.getAssociationsList().size() == 3); 

    onView(withId(R.id.associationsListView)).check(matches(isDisplayed())); 
    onData(anything()) 
      .inAdapterView(withId(R.id.associationsListView)) 
      .atPosition(0) 
      .perform(click()); 

    assertCurrentActivityIsInstanceOf(AssociationsListActivityTest.this 
      , AssociationsPageActivity.class); 

的方法，簡單地listActivity.addAssociation(association);確實associationArrayAdapter.add(association);。

的ArrayAdapter用於元素與ID添加到ListView（默認可見）R.id.associationsListView

當我運行這個測試，我得到以下錯誤：

android.support.test.espresso.base.DefaultFailureHandler$AssertionFailedWithCauseError: 'is displayed on the screen to the user' doesn't match the selected view. 
Expected: is displayed on the screen to the user 
Got: "ListView{id=2131427414, res-name=associationsListView, visibility=VISIBLE, width=996, height=0, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=42.0, y=42.0, child-count=0}" 

這是造成下面的斷言，onView(withId(R.id.associationsListView)).check(matches(isDisplayed()));

此外，當評論這個斷言，下一個例外導致以下異常：

android.support.test.espresso.PerformException: Error performing 'load adapter data' on view 'with id: ch.epfl.sweng.project:id/associationsListView'. 
... 
Caused by: java.lang.RuntimeException: Action will not be performed because the target view does not match one or more of the following constraints: 
(is assignable from class: class android.widget.AdapterView and is displayed on the screen to the user) 
Target view: "ListView{id=2131427414, res-name=associationsListView, visibility=VISIBLE, width=996, height=0, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=42.0, y=42.0, child-count=0}" 

我經歷了很多覆蓋這些異常的堆棧溢出線程，我用其他等價物替換了那些測試，但是這些錯誤仍然顯示出來，我不知道該怎麼做！謝謝你的幫助！

Answer 1

我發現有什麼問題！

我向ArrayAdapter添加元素的方法使用了runOnUIThread，但似乎測試並未等待此方法，因此associationsListView被認爲不會顯示給用戶！所以我固定我的方法listActivity.addAssociation(Association association)這樣的：

public void addAssociation(final Association association) { 
    final CountDownLatch latch = new CountDownLatch(1); 
    runOnUiThread(new Runnable() { 
     @Override 
     public void run() { 
      if (!associationList.contains(association)) { 
       associationArrayAdapter.add(association); 
      } 
      latch.countDown(); 
     } 
    }); 
    try { 
     latch.await(); 
    } catch (InterruptedException e) { 
     e.printStackTrace(); 
    } 
    if (!associationList.contains(association)) { 
     associationList.add(association); 
    } 
} 

測試的所有部分現在都通過了:)