The way Toasts are implemented makes it possible to detect a toast has been displayed. However there is no way to see if a Toast has been requested, thru a call to show()) or to block between the period of time between show() and when the toast has become visible. This is opens up unresolvable timing issues (that you can only address thru sleep & hope).
If you really really want to verify this, here's a not-so-pretty alternative using Mockito and a test spy:
public interface Toaster {
public void showToast(Toast t);
private static class RealToaster {
@Override
public void showToast(Toast t) {
t.show();
}
public static Toaster makeToaster() {
return new RealToaster();
}
}
Then in your test
public void testMyThing() {
Toaster spyToaster = Mockito.spy(Toaster.makeToaster());
getActivity().setToaster(spyToaster);
onView(withId(R.button)).perform(click());
getInstrumentation().runOnMainSync(new Runnable() {
@Override
public void run() {
// must do this on the main thread because the matcher will be interrogating a view...
Mockito.verify(spyToaster).showToast(allOf(withDuration(Toast.LENGTH_SHORT), withView(withText("hello world"));
});
}
// create a matcher that calls getDuration() on the toast object
Matcher<Toast> withDuration(int)
// create a matcher that calls getView() and applies the given view matcher
Matcher<Toast> withView(Matcher<View> viewMatcher)
another answer regarding this
if(someToast == null)
someToast = Toast.makeText(this, "sdfdsf", Toast.LENGTH_LONG);
boolean isShown = someToast.getView().isShown();
The accepted answer is a good one but didn't work for me. So I searched a bit and found this blog article.
This gave me an idea of how to do it and I updated the solution above.
First I implemented the ToastMatcher:
import android.os.IBinder;
import android.support.test.espresso.Root;
import android.view.WindowManager;
import org.hamcrest.Description;
import org.hamcrest.TypeSafeMatcher;
public class ToastMatcher extends TypeSafeMatcher<Root> {
@Override
public void describeTo(Description description) {
description.appendText("is toast");
}
@Override
public boolean matchesSafely(Root root) {
int type = root.getWindowLayoutParams().get().type;
if (type == WindowManager.LayoutParams.TYPE_TOAST) {
IBinder windowToken = root.getDecorView().getWindowToken();
IBinder appToken = root.getDecorView().getApplicationWindowToken();
if (windowToken == appToken) {
// windowToken == appToken means this window isn't contained by any other windows.
// if it was a window for an activity, it would have TYPE_BASE_APPLICATION.
return true;
}
}
return false;
}
}
Then I implemented my check methods like this:
public void isToastMessageDisplayed(int textId) {
onView(withText(textId)).inRoot(MobileViewMatchers.isToast()).check(matches(isDisplayed()));
}
MobileViewMatchers is a container for accessing the matchers. There I defined the static method isToast().
public static Matcher<Root> isToast() {
return new ToastMatcher();
}
First create a cutom Toast Matcher which we can use in our test cases -
public class ToastMatcher extends TypeSafeMatcher<Root> {
@Override public void describeTo(Description description) {
description.appendText("is toast");
}
@Override public boolean matchesSafely(Root root) {
int type = root.getWindowLayoutParams().get().type;
if ((type == WindowManager.LayoutParams.TYPE_TOAST)) {
IBinder windowToken = root.getDecorView().getWindowToken();
IBinder appToken = root.getDecorView().getApplicationWindowToken();
if (windowToken == appToken) {
//means this window isn't contained by any other windows.
return true;
}
}
return false;
}
}
Though the question has an accepted answer - which BTW does not work for me - I'd like to add my solution in Kotlin which I derived from Thomas R.'s answer:
package somepkg
import android.support.test.espresso.Espresso.onView
import android.support.test.espresso.Root
import android.support.test.espresso.matcher.ViewMatchers.withText
import android.view.WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
import android.view.WindowManager.LayoutParams.TYPE_TOAST
import org.hamcrest.Description
import org.hamcrest.Matcher
import org.hamcrest.TypeSafeMatcher
/**
* This class allows to match Toast messages in tests with Espresso.
*
* Idea taken from: https://stackoverflow.com/a/33387980
*
* Usage in test class:
*
* import somepkg.ToastMatcher.Companion.onToast
*
* // To assert a toast does *not* pop up:
* onToast("text").check(doesNotExist())
* onToast(textId).check(doesNotExist())
*
* // To assert a toast does pop up:
* onToast("text").check(matches(isDisplayed()))
* onToast(textId).check(matches(isDisplayed()))
*/
class ToastMatcher(private val maxFailures: Int = DEFAULT_MAX_FAILURES) : TypeSafeMatcher<Root>() {
/** Restrict number of false results from matchesSafely to avoid endless loop */
private var failures = 0
override fun describeTo(description: Description) {
description.appendText("is toast")
}
public override fun matchesSafely(root: Root): Boolean {
val type = root.windowLayoutParams.get().type
@Suppress("DEPRECATION") // TYPE_TOAST is deprecated in favor of TYPE_APPLICATION_OVERLAY
if (type == TYPE_TOAST || type == TYPE_APPLICATION_OVERLAY) {
val windowToken = root.decorView.windowToken
val appToken = root.decorView.applicationWindowToken
if (windowToken === appToken) {
// windowToken == appToken means this window isn't contained by any other windows.
// if it was a window for an activity, it would have TYPE_BASE_APPLICATION.
return true
}
}
// Method is called again if false is returned which is useful because a toast may take some time to pop up. But for
// obvious reasons an infinite wait isn't of help. So false is only returned as often as maxFailures specifies.
return (++failures >= maxFailures)
}
companion object {
/** Default for maximum number of retries to wait for the toast to pop up */
private const val DEFAULT_MAX_FAILURES = 5
fun onToast(text: String, maxRetries: Int = DEFAULT_MAX_FAILURES) = onView(withText(text)).inRoot(isToast(maxRetries))!!
fun onToast(textId: Int, maxRetries: Int = DEFAULT_MAX_FAILURES) = onView(withText(textId)).inRoot(isToast(maxRetries))!!
fun isToast(maxRetries: Int = DEFAULT_MAX_FAILURES): Matcher<Root> {
return ToastMatcher(maxRetries)
}
}
}
I hope this will be of help for later readers - the usage is described in the comment.
If you're using the newest Android Testing Tools from Jetpack, you know, that ActivityTestRule is deprecated and you should use ActivityScenario or ActivityScenarioRule(which contains the first).
Prerequisites. Create decorView variable and assign it before tests;
@Rule
public ActivityScenarioRule<FeedActivity> activityScenarioRule = new ActivityScenarioRule<>(FeedActivity.class);
private View decorView;
@Before
public void setUp() {
activityScenarioRule.getScenario().onActivity(new ActivityScenario.ActivityAction<FeedActivity>() {
@Override
public void perform(FeedActivityactivity activity) {
decorView = activity.getWindow().getDecorView();
}
});
}
Test itself
@Test
public void given_when_thenShouldShowToast() {
String expectedWarning = getApplicationContext().getString(R.string.error_empty_list);
onView(withId(R.id.button))
.perform(click());
onView(withText(expectedWarning))
.inRoot(withDecorView(not(decorView)))// Here we use decorView
.check(matches(isDisplayed()));
}
getApplicationContext() can be taken from androidx.test.core.app.ApplicationProvider.getApplicationContext;
I'm pretty new to this, but I made a base class 'BaseTest' that has all of my actions (swiping, clicking, etc.) and verifications (checking text views for content, etc.).
protected fun verifyToastMessageWithText(text: String, activityTestRule: ActivityTestRule<*>) {
onView(withText(text)).inRoot(withDecorView(not(activityTestRule.activity.window.decorView))).check(matches(isDisplayed()))
}
protected fun verifyToastMessageWithStringResource(id: Int, activityTestRule: ActivityTestRule<*>) {
onView(withText(id)).inRoot(withDecorView(not(activityTestRule.activity.window.decorView))).check(matches(isDisplayed()))
}
or any other custom inRoot checks
are throwing NoMatchingRootException even before the code passes to check method
You may just catch the exception and complete the test but that's not a good option since throwing and catching NoMatchingRootException consumes a lot of time in a comparison with the default test case. Seems that Espresso is waiting for the Root for a while
For this case is suggest just to give up with espresso here and use UiAutomator for this assertion. The Espresso and UiAutomator frameworks could easily work together in one environment.
val device: UiDevice
get() = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation())
fun assertPopupIsNotDisplayed() {
device.waitForIdle()
assertFalse(device.hasObject(By.text(yourText))))
}
fun assertPopupIsDisplayed() {
device.waitForIdle()
assertTrue(device.hasObject(By.text(yourText))))
}
For kotlin, I had to use the apply extension function, and this worked for me.
1- declare your ToastMatcher class in the androidTest folder:
class ToastMatcher : TypeSafeMatcher<Root?>() {
override fun matchesSafely(item: Root?): Boolean {
val type: Int? = item?.windowLayoutParams?.get()?.type
if (type == WindowManager.LayoutParams.FIRST_APPLICATION_WINDOW) {
val windowToken: IBinder = item.decorView.windowToken
val appToken: IBinder = item.decorView.applicationWindowToken
if (windowToken === appToken) { // means this window isn't contained by any other windows.
return true
}
}
return false
}
override fun describeTo(description: Description?) {
description?.appendText("is toast")
}
}
2- Then you use like this to test that the toast message actually displays
//Change YourActivity by the activity you are testing
@Rule
public ActivityScenarioRule<YourActivity> activityRule
= new ActivityScenarioRule<>(YourActivity.class);
@Test
public void testWithToasts() {
//Arrange and act code
//Modify toast_msg to your own string resource
onView(withText(R.string.toast_msg)).
inRoot(RootMatchers.withDecorView(not(decorView)))
.check(matches(isDisplayed()));
}