Code Inspection: NUnit. Expected non-abstract class implementing IEnumerable

NUnit's TestCaseSource attribute is used to identify the source from which the argument(s) will be provided for a parameterized test. The class that provides test cases must have a default constructor and implement IEnumerable. If the test source class does not implement IEnumerable, ReSharper issues a warning.

Note that NUnit allows different ways of specifying test case sources. For details, refer to the TestCaseSourceAttribute documentation.