Android Espresso onData with doesNotExist

Question

I am trying to verify that a ListView does not contain a particular item. Here's the code I'm using:

onData(allOf(is(instanceOf(Contact.class)), is(withContactItemName(is("TestName")))))
      .check(doesNotExist());

When the name exists, I correctly get an error because of check(doesNotExist()). When the name does not exist, I get the following error, because allOf(...) doesn't match anything:

Caused by: java.lang.RuntimeException: No data found matching: 
(is an instance of layer.sdk.contacts.Contact and is with contact item name:
is "TestName")

How can I get functionality like onData(...).check(doesNotExist())?

EDIT:

I have a terrible hack to get the functionality I'd like by using try/catch and inspecting the event's getCause(). I would love to replace this with a good technique.

score 14 · Accepted Answer · edited Sep 15 '21 at 19:47

According to Espresso samples you must not use onData(...) to check if view doesn't exists in adapter. Check this out - link. Read "Asserting that a data item is not in an adapter" part. You have to use a matcher together with onView() that finds the AdapterView.

Based on Espresso samples from link above:

matcher:

 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;
         }
     };
 }

then onView(...), where R.id.list is the id of your adapter ListView:

 @SuppressWarnings("unchecked")
 public void testDataItemNotInAdapter(){
     onView(withId(R.id.list))
         .check(matches(not(withAdaptedData(is(withContactItemName("TestName"))))));
 }

And one more suggestion - to avoid writing is(withContactItemName(is("TestName")) add below code to your matcher:

    public static Matcher<Object> withContactItemName(String itemText) {
        checkArgument( itemText != null );
        return withContactItemName(equalTo(itemText));
    }

then you'll have more readable and clear code is(withContactItemName("TestName")

Android Espresso onData with doesNotExist

1 Answers1

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