public void Test_UserUnfollowUserRequest_Validate_Throws_Exceptions() { // username is null var request = new UserUnfollowUserRequest(); Action act = () => request.Validate(); act.Should().Throw <ArgumentNullException>(); // empty username request = new UserUnfollowUserRequest { Username = string.Empty }; act = () => request.Validate(); act.Should().Throw <ArgumentException>(); // username with spaces request = new UserUnfollowUserRequest { Username = "******" }; act = () => request.Validate(); act.Should().Throw <ArgumentException>(); }