toBeNull(); expect('')->not->toBeNull(); }); test('failures', function () { expect('hello')->toBeNull(); })->throws(ExpectationFailedException::class); test('failures with custom message', function () { expect('hello')->toBeNull('oh no!'); })->throws(ExpectationFailedException::class, 'oh no!'); test('not failures', function () { expect(null)->not->toBeNull(); })->throws(ExpectationFailedException::class);