Android Espresso - 测试 ListView 行

Question

我目前正在尝试使用 Espresso 在 android 上测试 ListView，并使用自定义 ArrayAdapter。 这是测试：

 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);

listActivity.addAssociation(association); 方法只执行associationArrayAdapter.add(association);。

ArrayAdapter用于将元素添加到ID为R.id.associationsListView的ListView（默认可见）

当我运行这个测试时，我收到以下错误：

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}"

这是由以下断言引起的，onView(withId(R.id.associationsListView)).check(matches(isDisplayed()));

同样在评论这个断言时，下一个会导致以下异常：

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}"

我经历了很多覆盖这些异常的堆栈溢出线程，我用其他等价物替换了这些测试，但这些错误仍然出现我不知道该怎么办！感谢您的帮助！

Answer 1

我发现了问题所在！

我将元素添加到ArrayAdapter 的方法使用了runOnUIThread，但似乎测试并未等待此方法，因此associationsListView 被认为未向用户显示！所以我像这样修复了我的方法listActivity.addAssociation(Association association)：

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);
    }
}

现在测试的所有部分都通过了 :)