Hamcrest assertThat ambiguous?

java junit4 hamcrest
MartinL picture MartinL · Oct 31, 2011 · Viewed 11k times · Source

I got some samplecode from a college, imported the project and try to run the Tests: The method assertThat(Integer, Matcher) is ambiguous for the type MyClass

Every assertThat is marked red with the same error-message so i tried to write the simpliest test which describes the problem:

import static org.hamcrest.MatcherAssert.*;
import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

@Test
public void whenAssertThatThenItIsAmbiguous() {
    List<String> list = Arrays.asList("A", "B", "C");
    assertThat(list.size(), is(3));
}

after I scroll over assertThat I get the following message:

The method assertThat(Integer, Matcher<Integer>) is ambiguous for the type MyClass

I searched google and stackoverflow but couldn't find anybody with the same problem... Please help.

EDIT1:

Solution:

import static org.junit.Assert.*; // delete this line

Answer

pholser picture pholser · Oct 31, 2011

Both org.junit.Assert and org.hamcrest.MatcherAssert declare assertThat(T, Matcher<T>). Choose to static-import one or the other, but not both, and you should be OK.

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