Wiki on ITestCaseData seems to be out of sync with the code

[provegard]

The wiki (https://github.com/nunit/docs/wiki/TestCaseData) reads:

Although any object implementing ITestCaseData may be used to provide extended test case information [...]

However, when I create a custom object implementing the ITestCaseData interface, I get:

An exception was thrown while loading the test.
System.InvalidCastException: Unable to cast object of type 'CustomTestCaseData' to type 'NUnit.Framework.Internal.TestCaseParameters'.
   at NUnit.Framework.TestCaseSourceAttribute.<BuildFrom>d__21.MoveNext()
   at NUnit.Framework.Internal.Builders.DefaultTestCaseBuilder.BuildFrom(IMethodInfo method, Test parentSuite)
   at NUnit.Framework.Internal.Builders.NUnitTestFixtureBuilder.AddTestCasesToFixture(TestFixture fixture)
   at NUnit.Framework.Internal.Builders.NUnitTestFixtureBuilder.BuildFrom(ITypeInfo typeInfo)
   at NUnit.Framework.Internal.Builders.DefaultSuiteBuilder.BuildFrom(ITypeInfo typeInfo)

[blachniet]

This appears to work fine in NUnit 2.x, but it's broken in 3.2.1.

[CharliePoole]

@blachniet We accepted this as a documentation bug because the docs are incorrect, reflecting the V2 behavior of the interface.

I mention that so you will understand that this issue won't result in anything changing in the NUnit codebase. Currently, the quoted statement "...any object implementing ITestCaseData..." is incorrect for NUnit V3. There's no particular reason an extension can't return the classes we provide internally in the framework, or extend them, rather than creating their own implementation from scratch.

[blachniet]

Ok, thank you for clarifying that. Is TestCaseData the appropriate class to derive from?

[CharliePoole]

If you want the fluent interface, yes. But if it's an extension that provides data it probably makes more sense to derive from it's base class, NUnit.Framework.Internal.TestCaseParameters. That's what all the NUnit attributes that provide test cases use.

[rprouse]

I have updated the documentation for TestCaseData and TestFixtureData.