Espresso 测试方案

本文档介绍如何设置各种常见的 Espresso 测试。

匹配另一个视图旁边的视图

布局可能会包含某些本身不具唯一性的视图。例如,联系人表中的某个重复通话按钮可以与视图层次结构中的其他通话按钮具有相同的 R.id、包含相同的文本,并具有相同的属性。

例如,在此 activity 中,包含文本 "7" 的视图在多行间重复:

一个列表 activity,在一个包含 3 个项目的列表中显示了同一视图元素的 3 个副本

通常,非唯一视图会与位于其旁边的某个唯一标签配对,例如通话按钮旁边的联系人姓名。在这种情况下,您可以使用 hasSibling() 匹配器缩小选择范围:

Kotlin

onView(allOf(withText("7"), hasSibling(withText("item: 0"))))
    .perform(click())

Java

onView(allOf(withText("7"), hasSibling(withText("item: 0"))))
    .perform(click());

匹配操作栏内的视图

ActionBarTestActivity 具有两个不同的操作栏:一个普通操作栏和一个根据选项菜单创建的上下文操作栏。这两个操作栏都有一个始终可见的项和两个仅在溢出菜单中可见的项。当用户点击某个项目时,它会将 TextView 更改为所点击项目的内容。

匹配两个操作栏上的可见图标非常简单,如以下代码段所示:

Kotlin

fun testClickActionBarItem() {
    // We make sure the contextual action bar is hidden.
    onView(withId(R.id.hide_contextual_action_bar))
        .perform(click())

    // Click on the icon - we can find it by the r.Id.
    onView(withId(R.id.action_save))
        .perform(click())

    // Verify that we have really clicked on the icon
    // by checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Save")))
}

Java

public void testClickActionBarItem() {
    // We make sure the contextual action bar is hidden.
    onView(withId(R.id.hide_contextual_action_bar))
        .perform(click());

    // Click on the icon - we can find it by the r.Id.
    onView(withId(R.id.action_save))
        .perform(click());

    // Verify that we have really clicked on the icon
    // by checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Save")));
}

保存按钮在 Activity 顶部的操作栏上

上下文操作栏的代码看起来完全相同:

Kotlin

fun testClickActionModeItem() {
    // Make sure we show the contextual action bar.
    onView(withId(R.id.show_contextual_action_bar))
        .perform(click())

    // Click on the icon.
    onView((withId(R.id.action_lock)))
        .perform(click())

    // Verify that we have really clicked on the icon
    // by checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Lock")))
}

Java

public void testClickActionModeItem() {
    // Make sure we show the contextual action bar.
    onView(withId(R.id.show_contextual_action_bar))
        .perform(click());

    // Click on the icon.
    onView((withId(R.id.action_lock)))
        .perform(click());

    // Verify that we have really clicked on the icon
    // by checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Lock")));
}

锁定按钮在 Activity 顶部的操作栏上

点击溢出菜单中的项目对于普通操作栏来说稍微复杂一些,因为某些设备具有硬件溢出菜单按钮,该按钮会打开选项菜单中的溢出项目,而有些设备具有软件溢出菜单按钮,该按钮会打开常规的溢出菜单。幸运的是,Espresso 为我们处理了这个问题

对于普通操作栏:

Kotlin

fun testActionBarOverflow() {
    // Make sure we hide the contextual action bar.
    onView(withId(R.id.hide_contextual_action_bar))
        .perform(click())

    // Open the options menu OR open the overflow menu, depending on whether
    // the device has a hardware or software overflow menu button.
    openActionBarOverflowOrOptionsMenu(
            ApplicationProvider.getApplicationContext<Context>())

    // Click the item.
    onView(withText("World"))
        .perform(click())

    // Verify that we have really clicked on the icon by checking
    // the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("World")))
}

Java

public void testActionBarOverflow() {
    // Make sure we hide the contextual action bar.
    onView(withId(R.id.hide_contextual_action_bar))
        .perform(click());

    // Open the options menu OR open the overflow menu, depending on whether
    // the device has a hardware or software overflow menu button.
    openActionBarOverflowOrOptionsMenu(
            ApplicationProvider.getApplicationContext());

    // Click the item.
    onView(withText("World"))
        .perform(click());

    // Verify that we have really clicked on the icon by checking
    // the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("World")));
}

溢出菜单按钮可见,并且一个列表显示在屏幕顶部附近的操作栏下方

在具有硬件溢出菜单按钮的设备上,如下所示:

没有溢出菜单按钮,并且一个列表显示在屏幕底部附近

对于上下文操作栏,同样非常简单:

Kotlin

fun testActionModeOverflow() {
    // Show the contextual action bar.
    onView(withId(R.id.show_contextual_action_bar))
        .perform(click())

    // Open the overflow menu from contextual action mode.
    openContextualActionModeOverflowMenu()

    // Click on the item.
    onView(withText("Key"))
        .perform(click())

    // Verify that we have really clicked on the icon by
    // checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Key")))
    }
}

Java

public void testActionModeOverflow() {
    // Show the contextual action bar.
    onView(withId(R.id.show_contextual_action_bar))
        .perform(click());

    // Open the overflow menu from contextual action mode.
    openContextualActionModeOverflowMenu();

    // Click on the item.
    onView(withText("Key"))
        .perform(click());

    // Verify that we have really clicked on the icon by
    // checking the TextView content.
    onView(withId(R.id.text_action_bar_result))
        .check(matches(withText("Key")));
    }
}

溢出菜单按钮显示在操作栏中,选项列表显示在屏幕顶部附近的操作栏下方

如需查看这些示例的完整代码,请查看 GitHub 上的 ActionBarTest.java 示例。

断言视图未显示

执行一系列操作后,您肯定需要断言被测界面的状态。有时,这可能是负面的情况,例如当事情没有发生时。请注意,您可以使用 ViewAssertions.matches() 将任何 hamcrest 视图匹配器变为 ViewAssertion

在以下示例中,我们采用 isDisplayed() 匹配器,并使用标准的 not() 匹配器将其反转:

Kotlin

import androidx.test.espresso.Espresso.onView
import androidx.test.espresso.assertion.ViewAssertions.matches
import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
import androidx.test.espresso.matcher.ViewMatchers.withId
import org.hamcrest.Matchers.not

onView(withId(R.id.bottom_left))
    .check(matches(not(isDisplayed())))

Java

import static androidx.test.espresso.Espresso.onView;
import static androidx.test.espresso.assertion.ViewAssertions.matches;
import static androidx.test.espresso.matcher.ViewMatchers.isDisplayed;
import static androidx.test.espresso.matcher.ViewMatchers.withId;
import static org.hamcrest.Matchers.not;

onView(withId(R.id.bottom_left))
    .check(matches(not(isDisplayed())));

如果相应视图仍然是层次结构的一部分,则上述方法有效。否则,您将收到 NoMatchingViewException,并且需要使用 ViewAssertions.doesNotExist()

断言视图不存在

如果该视图从视图层次结构中消失(当某项操作导致转换到另一个 activity 时,可能会发生这种情况),则应使用 ViewAssertions.doesNotExist()

Kotlin

import androidx.test.espresso.Espresso.onView
import androidx.test.espresso.assertion.ViewAssertions.doesNotExist
import androidx.test.espresso.matcher.ViewMatchers.withId

onView(withId(R.id.bottom_left))
    .check(doesNotExist())

Java

import static androidx.test.espresso.Espresso.onView;
import static androidx.test.espresso.assertion.ViewAssertions.doesNotExist;
import static androidx.test.espresso.matcher.ViewMatchers.withId;

onView(withId(R.id.bottom_left))
    .check(doesNotExist());

断言数据项不在适配器中

如需证明特定的数据项不在 AdapterView 中,您的操作方法应该略有不同。我们必须查找相关的 AdapterView 并查询其持有的数据。我们不需要使用 onData(),而是使用 onView() 查找 AdapterView,然后使用另一个匹配器来处理视图内的数据。

首先是匹配器:

Kotlin

private fun withAdaptedData(dataMatcher: Matcher<Any>): Matcher<View> {
    return object : TypeSafeMatcher<View>() {

        override fun describeTo(description: Description) {
            description.appendText("with class name: ")
            dataMatcher.describeTo(description)
        }

        public override fun matchesSafely(view: View) : Boolean {
            if (view !is AdapterView<*>) {
                return false
            }

            val adapter = view.adapter
            for (i in 0 until adapter.count) {
                if (dataMatcher.matches(adapter.getItem(i))) {
                    return true
                }
            }

            return false
        }
    }
}

Java

private static Matcher<View> withAdaptedData(final Matcher<Object> dataMatcher) {
    return new TypeSafeMatcher<View>() {

        @Override
        public void describeTo(Description description) {
            description.appendText("with class name: ");
            dataMatcher.describeTo(description);
        }

        @Override
        public boolean matchesSafely(View view) {
            if (!(view instanceof AdapterView)) {
                return false;
            }

            @SuppressWarnings("rawtypes")
            Adapter adapter = ((AdapterView) view).getAdapter();
            for (int i = 0; i < adapter.getCount(); i++) {
                if (dataMatcher.matches(adapter.getItem(i))) {
                    return true;
                }
            }

            return false;
        }
    };
}

然后,我们只需要使用 onView() 来查找 AdapterView

Kotlin

fun testDataItemNotInAdapter() {
    onView(withId(R.id.list))
          .check(matches(not(withAdaptedData(withItemContent("item: 168")))))
    }
}

Java

@SuppressWarnings("unchecked")
public void testDataItemNotInAdapter() {
    onView(withId(R.id.list))
          .check(matches(not(withAdaptedData(withItemContent("item: 168")))));
    }
}

我们有一个断言,如果具有 ID 列表的适配器视图中存在等于“item: 168”的项,该断言将失败。

如需查看完整示例,请查看 GitHub 上的 AdapterViewTest.java 类中的 testDataItemNotInAdapter() 方法。

使用自定义故障处理程序

将 Espresso 中的默认 FailureHandler 替换为自定义配置可实现其他或不同的错误处理,如截取屏幕截图或传递额外的调试信息。

CustomFailureHandlerTest 示例演示了如何实现自定义失败处理程序:

Kotlin

private class CustomFailureHandler(targetContext: Context) : FailureHandler {
    private val delegate: FailureHandler

    init {
        delegate = DefaultFailureHandler(targetContext)
    }

    override fun handle(error: Throwable, viewMatcher: Matcher<View>) {
        try {
            delegate.handle(error, viewMatcher)
        } catch (e: NoMatchingViewException) {
            throw MySpecialException(e)
        }

    }
}

Java

private static class CustomFailureHandler implements FailureHandler {
    private final FailureHandler delegate;

    public CustomFailureHandler(Context targetContext) {
        delegate = new DefaultFailureHandler(targetContext);
    }

    @Override
    public void handle(Throwable error, Matcher<View> viewMatcher) {
        try {
            delegate.handle(error, viewMatcher);
        } catch (NoMatchingViewException e) {
            throw new MySpecialException(e);
        }
    }
}

此失败处理程序会抛出 MySpecialException 而不是 NoMatchingViewException,并将所有其他失败情况委托给 DefaultFailureHandler。您可以在测试的 setUp() 方法中向 Espresso 注册 CustomFailureHandler

Kotlin

@Throws(Exception::class)
override fun setUp() {
    super.setUp()
    getActivity()
    setFailureHandler(CustomFailureHandler(
            ApplicationProvider.getApplicationContext<Context>()))
}

Java

@Override
public void setUp() throws Exception {
    super.setUp();
    getActivity();
    setFailureHandler(new CustomFailureHandler(
            ApplicationProvider.getApplicationContext()));
}

如需了解详情,请参阅 FailureHandler 接口和 Espresso.setFailureHandler()

以非默认窗口为目标

Android 支持多个窗口。通常,这对用户和应用开发者是透明的,但在某些情况下,系统会显示多个窗口,例如在搜索 widget 中的主应用窗口上绘制自动填充窗口时。为了简化操作,默认情况下,Espresso 使用启发法来猜测您想要与哪个 Window 交互。这种启发法几乎总是足够好;不过,在极少数情况下,您需要指定互动应定位到哪个窗口。为此,您可以提供自己的根窗口匹配器或 Root 匹配器:

Kotlin

onView(withText("South China Sea"))
    .inRoot(withDecorView(not(`is`(getActivity().getWindow().getDecorView()))))
    .perform(click())

Java

onView(withText("South China Sea"))
    .inRoot(withDecorView(not(is(getActivity().getWindow().getDecorView()))))
    .perform(click());

ViewMatchers 一样,我们提供了一组预先提供的 RootMatchers。当然,您始终可以实现自己的Matcher对象。

请查看 GitHub 上的 MultipleWindowTest 示例

您可以使用 addHeaderView()addFooterView() 方法将页眉和页脚添加到 ListViews。为了确保 Espresso.onData() 知道要匹配哪个数据对象,请务必将预设的数据对象值作为第二个参数传递给 addHeaderView()addFooterView()。例如:

Kotlin

const val FOOTER = "FOOTER"
...
val footerView = layoutInflater.inflate(R.layout.list_item, listView, false)
footerView.findViewById<TextView>(R.id.item_content).text = "count:"
footerView.findViewById<TextView>(R.id.item_size).text
        = data.size.toString
listView.addFooterView(footerView, FOOTER, true)

Java

public static final String FOOTER = "FOOTER";
...
View footerView = layoutInflater.inflate(R.layout.list_item, listView, false);
footerView.findViewById<TextView>(R.id.item_content).setText("count:");
footerView.findViewById<TextView>(R.id.item_size).setText(String.valueOf(data.size()));
listView.addFooterView(footerView, FOOTER, true);

然后,您可以为页脚编写一个匹配器:

Kotlin

import org.hamcrest.Matchers.allOf
import org.hamcrest.Matchers.instanceOf
import org.hamcrest.Matchers.`is`

fun isFooter(): Matcher<Any> {
    return allOf(`is`(instanceOf(String::class.java)),
            `is`(LongListActivity.FOOTER))
}

Java

import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.is;

@SuppressWarnings("unchecked")
public static Matcher<Object> isFooter() {
    return allOf(is(instanceOf(String.class)), is(LongListActivity.FOOTER));
}

在测试中加载视图很简单:

Kotlin

import androidx.test.espresso.Espresso.onData
import androidx.test.espresso.action.ViewActions.click
import androidx.test.espresso.sample.LongListMatchers.isFooter

fun testClickFooter() {
    onData(isFooter())
        .perform(click())

    // ...
}

Java

import static androidx.test.espresso.Espresso.onData;
import static androidx.test.espresso.action.ViewActions.click;
import static androidx.test.espresso.sample.LongListMatchers.isFooter;

public void testClickFooter() {
    onData(isFooter())
        .perform(click());

    // ...
}

请查看完整代码示例,可在 GitHub 上的 AdapterViewTest.javatestClickFooter() 方法中找到。