public void GetAll() { //Arrange _mock.Setup(s => s.GetAll()).Returns(_exercises); //Act var result = _exerciseController.GetAll(); var exercisesResult = result as OkNegotiatedContentResult <List <Exercise> >; //Assert Assert.IsInstanceOfType(result, typeof(OkNegotiatedContentResult <List <Exercise> >)); Assert.IsTrue(exercisesResult.Content.Count() > 0); }