Add name parameter to argThat #1932
Description
Argument matchers that are created with argThat using lambdas create an unreadable output, that does not really help:
@Test
void test() {
Consumer c = mock(Consumer.class);
c.accept(null);
verify(c, never()).accept(argThat(arg -> arg == null)); // <-- complex check here
}org.mockito.exceptions.verification.NeverWantedButInvoked:
consumer.accept(
<Test$$ lambda$ 5 4 4/ 0x 0 0 0 0 0 0 0 8 0 0 5eb 8 4 0>
);
Never wanted here:
-> at com.example.Test.test(Test.java:1077)
But invoked here:
-> at com.example.Test.test(Test.java:1076)
at com.example.Test.test(Test.java:1077)I searched a bit in the internet whether it is possible to somehow get a useful name for lambdas, but that doesn't seem to be possible. So instead, I would like to have an argThat method with an additional name (or description or message) parameter.
Example:
@Test
void test() {
Consumer c = mock(Consumer.class);
c.accept(null);
verify(c, never()).accept(argThat("is null", arg -> arg == null));
}org.mockito.exceptions.verification.NeverWantedButInvoked:
consumer.accept(
"is null"
);
Never wanted here:
-> at com.example.Test.test(Test.java:1077)
But invoked here:
-> at com.example.Test.test(Test.java:1076)
at com.example.Test.test(Test.java:1077)This is already possible right now, but needs to be copied for every project:
public static <T> T namedArgThat(final String name, final ArgumentMatcher<T> matcher) {
return argThat(new ArgumentMatcher<>() {
@Override
public boolean matches(final T argument) {
return matcher.matches(argument);
}
@Override
public String toString() {
return name;
}
});
}It would be nice if such a method could be added to the library itself.
The method is intended to be used with lambda expressions only.
As an alternative a static ArgumentMatcher#named(String, ArgumentMatcher) would work as well. Maybe this is even more useful, as it can be used for nested matchers as well.