android tutorial - Custom matcher for testing TextView in Android Espresso | Developer android - android app development - android studio - android app developement
Example of Custom matcher for testing TextView error message
- Create a class name ErrorMatcher inside your test package with below code:
public class ErrorMatcher {
@NonNull
public static Matcher<View> withError(final String expectedErrorText) {
Checks.checkNotNull(expectedErrorText);
return new BoundedMatcher<View, TextView>(TextView.class) {
@Override
public void describeTo(final Description description) {
description.appendText("error text: ");
stringMatcher.describeTo(description);
}
@Override
public boolean matchesSafely(final TextView textView) {
return expectedErrorText.equals(textView.getError().toString());
}
};
}
}click below button to copy code from our android learning website - android tutorial - team
Matching logic is to find the TextView element, which error message text is equal to expected error text value, going through the subset of TextView fields present in the layout hierarchy. describeTo method is used for debug output.
- Then you can use your custom matcher in the test case as shown below:
@Test
public void verifiesSignInErrorIsShown() {
onView(withId(R.id.email_sign_in_button)).perform(click());
onView(ErrorMatcher.withError("Your error text")).check(matches(isDisplayed()));
}