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

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");

Answer 2

catch-exception makes the example of Freiheit a bit more concise:

catchException(a).myMethod();
assertFalse(caughtException() instanceof ExceptionNotToThrow);

Answer 3

Another latest solution could be using Junit5 assertDoesNotThrow:

assertDoesNotThrow( () -> myMethod() , "MyException is not thrown")

Answer 4

Use @Test(expected = Test.None::class) (in Kotlin)