Why doesn't JUnit provide assertNotEquals methods?

java junit assert
Chris B picture Chris B · Jul 8, 2009 · Viewed 174.3k times · Source

Does anybody know why JUnit 4 provides assertEquals(foo,bar) but not assertNotEqual(foo,bar) methods?

It provides assertNotSame (corresponding to assertSame) and assertFalse (corresponding to assertTrue), so it seems strange that they didn't bother including assertNotEqual.

By the way, I know that JUnit-addons provides the methods I'm looking for. I'm just asking out of curiosity.

Answer

Joachim Sauer picture Joachim Sauer · Sep 23, 2009

I'd suggest you use the newer assertThat() style asserts, which can easily describe all kinds of negations and automatically build a description of what you expected and what you got if the assertion fails:

assertThat(objectUnderTest, is(not(someOtherObject)));
assertThat(objectUnderTest, not(someOtherObject));
assertThat(objectUnderTest, not(equalTo(someOtherObject)));

All three options are equivalent, choose the one you find most readable.

To use the simple names of the methods (and allow this tense syntax to work), you need these imports:

import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;

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