Examples of how to test the validation functionality

[BenjamenMeyer]

You mention in the README providing tests for the validation functions. It would be helpful to have some examples of the tests documented so that people know the proper way to test the validation functionality.

For instance: https://github.com/BenjamenMeyer/deuterium/blob/enhancement_input_validation/deuterium/tests/test_validation.py#L166

[painterjd]

Yeah, good idea. Thanks.