Testing validation rules & validators

Validation rules and message classes are inherently easy to unit test. There are some tricks that might help make it even easier, though.

Test framework integration

The validation framework itself is tested using NUnit. If you use this framework then you might want to take a look at the following classes from the test project CSF.Validation.Tests:

• CSF.Validation.ValidationResultConstraint
• CSF.Validation.Rules.RuleResultConstraint
• CSF.Validation.Is

These classes provide integration with NUnit to write assertions for validation results and the results from individual validation rules.

If you additionally use AutoFixture & Moq then the class CSF.Validation.IntegrationTestingAttribute might also be of interest to you.

Testing a validator itself

The implementation of the interface IValidatesValidationManifest may be used to perform a sanity-check upon a validator. This process does not guarantee that your validator is error-free but it can catch and point out a number of common errors.

If you create/scaffold a service provider within your integration tests, then you may resolve this service and use it to "validate your validators" and get a test result. See the test ValidationManifestValidatorTests.ValidateAsyncShouldReturnPassResultForItsOwnManifest for an example of using this service to validate a validator.