How do you unittest exceptions in Dart?

Question

Consider a function that does some exception handling based on the arguments passed:

List range(start, stop) {
    i         


        

Answer 1

An exception is checked using throwsA with TypeMatcher.

Note: isInstanceOf is now deprecated.

List range(start, stop) {
    if (start >= stop) {
      throw new ArgumentError("start must be less than stop");
    }
    // remainder of function
}


test("check argument error", () {
  expect(() => range(1, 2), throwsA(TypeMatcher()));
});