Espresso：如何测试ImageButton的背景可绘制对象

Question

我似乎已经跌入谷底，试图找到一种解决方案，该方案可以在我的Espresso测试中测试我的ImageButton是否具有特定的背景可绘制。但是我一直收到下面粘贴的错误。我已经提供了我认为相关的尽可能多的代码。

ImageButton

            <ImageButton
            android:id="@+id/image_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/ic_background_selector"
            android:clickable="true"
            android:src="@drawable/background" />

选择器

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/ic_background_error" android:state_activated="true" />
<item android:drawable="@drawable/ic_background_okay" android:state_activated="false" />
</selector>

自定义匹配项：

fun matchColor(expectedId: Int): Matcher<View> {
return object : BoundedMatcher<View, ImageButton>(ImageButton::class.java) {
    override fun describeTo(description: Description?) {
        description?.appendText("with text color: ")
        description?.appendValue(expectedId)
    }

    override fun matchesSafely(item: ImageButton?): Boolean {
        return item?.context?.resources?.getDrawable(expectedId)?.constantState == item?.drawable?.constantState
    }

}

}

测试：

        onView(withId(R.id.image_button)).check(matches(matchColor(R.drawable.ic_background_okay)))

我收到以下错误：

androidx.test.espresso.base.DefaultFailureHandler$AssertionFailedWithCauseError: 'with text 
color: <2131165331>' doesn't match the selected view. Expected: with text color: 
<2131165331>Got: "AppCompatImageButton{id=2131296363, ...}

Answer 1

我建议您在更改图像更改时设置标签，并比较标签而不是图像本身。如果您没有设置标签并且不知道如何编写自定义匹配器，则可以通过活动找到imagebutton，并使用与应用程序中相同的逻辑来比较当前显示的图像。

 @Test
    fun test_image_button_compare_success() {
        val activity = getActivityInstance();
        val imageButton= activity?.findViewById((R.id.image_button)) as ImageButton
        assertTrue(1==1) //Replace here with your control using image button
    }

正在获取活动实例为taken from here

私人活动getActivityInstance（）{final Activity [] currentActivity = {null};

getInstrumentation().runOnMainSync(new Runnable(){
  public void run(){
    Collection<Activity> resumedActivity = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED);
    Iterator<Activity> it = resumedActivity.iterator();
    currentActivity[0] = it.next();
  }
});

return currentActivity[0];

}