public void Create_throws_on_invalid_arguments_with_custom_metadata()
 {
     Assert.That(
         () => Commands.AddOneAsync <TestModel, TestMetadata>(null),
         Throws.TypeOf <ArgumentNullException>());
 }
 public void Create_throws_on_invalid_arguments()
 {
     Assert.That(
         () => Commands.AddOneAsync <TestModel>(null),
         Throws.TypeOf <ArgumentNullException>());
 }