How can I test if a particular exception is not thrown?

Question

Can I test whether a particular Exception is not thrown?

The other way round is easy using @Test[expect=MyException].

But how can I negate this?

Answer 1

If you want to test if a particular Exception is not thrown in a condition where other exceptions could be thrown, try this:

try {   myMethod(); } catch (ExceptionNotToThrow entt){   fail("WHOOPS! Threw ExceptionNotToThrow" + entt.toString); } catch (Throwable t){   //do nothing since other exceptions are OK } assertTrue(somethingElse); //done! 

Answer 2

You can do the following using assertj

if you want to check if exception is not thrown then

Throwable throwable = catchThrowable(() -> sut.method());  assertThat(throwable).isNull(); 

or you expect to throw

Throwable throwable = catchThrowable(() -> sut.method());  assertThat(throwable).isInstanceOf(ClassOfExecption.class)                      .hasMessageContaining("expected message");