How to mock exception types in "Throws" and "ThrowsAsync"

Question

I would like to write one unit test for a set of different exception types. My common approach is to use InlineAutoMoqData for a certain set of test inputs. This works fine for values but I cannot get it working for types.

Below you can find my idea / wished solution:

[Theory]
[InlineAutoMockData(typeOf(HttpRequestException)] 
[InlineAutoMockData(typeOf(InvalidOperationException)] 
public async void MyTestFunction_Should_HandleExceptions(Type exceptionType, Mock<HttpClient> clientMock)
{
    // Arrange
    var cut = CreateCut();
    clientMock.Setup(c => c.SendAsync()).ThrowsAsync(new Exception()); // here I want to  create a generic Exception dependend on the exceptionType instead of "new Exception"

   // Act
   var result = cut.DoSomething();
   
   // Assert
   result.Should().BeTrue();
}

I could add a switch case checking "exceptionType" and moq the client dependend on it. This solution works but does not feel "right". I think there has to be a more elegant solution to it.

Answer 1

You can use the Activator to create an object from a type.

clientMock.Setup(c => 
   c.SendAsync()).ThrowsAsync((Exception) Activator.CreateInstance(exceptionType));