Dart Test using type check on Exception is returning wrong result

Question

I have this test that does fail when run. I am not sure why though since the a should be true. Can somebody explain me why?

  test('test error', () async {
    const error = Exception;
    const a = error is Exception;
    expect(a, true);
  });

Answer 1

error is not an instance of an Exception. error is the Exception type, and x is T checks if x is an instance of T. Therefore:

• Exception() is Exception would be true.
• error is Exception (equivalent to Exception is Exception) would be false.
• error is Type (equivalent to Exception is Exception) would be true.
• error == Exception (equivalent to Exception == Exception) would be true.