Assert.IsNotInstanceOf - jnm2/nunit-docs-wiki GitHub Wiki
Assert.IsNotInstanceOf succeeds if the object provided as an actual value is not an instance of the expected type.
Assert.IsNotInstanceOf(Type expected, object actual);
Assert.IsNotInstanceOf(Type expected, object actual,
string message, params object[] parms);
Assert.IsNotInstanceOf<T>(object actual);
Assert.IsNotInstanceOf<T>(object actual,
string message, params object[] parms);