public void BeCreatedResult_Throws_When_Subject_Isnt_ContentResult() { // Arrange var target = new DummyResult(); var sut = new ResultAssertions(target); // Act & Assert sut.Invoking(x => x.BeCreatedResult()) .Should() .Throw <XunitException>() .WithMessage($"Expected result to be of type Microsoft.AspNetCore.Mvc.ContentResult, but found {target.GetType().FullName}."); }