Add analyzer for unnecessary [TestFixture] attributes

[sdrager-emoney]

With NUnit 2.5, the [TestFixture] attribute is optional--the existence of a [Test] or [TestCase] is enough. It would be nice to have an analyzer option to enforce not using the attribute since it is now generally redundant.

Thank you

[manfred-brands]

@sdrager-emoney Thanks for your suggestion. Personally I still put the [TestFixture] on all tests. This make it clear to me. Especially in case of a derived class which itself doesn't contain any [Test] only some overrides of a base class.

Having said that, I can always disable such a rule if it existed.
Are you willing to put up PR for such a rule?

[andrewimcclement]

If we wanted to do this, we could possibly just mark [TestFixture] as [Obsolete] in NUnit, though doing that is less flexible than having a code analysis rule.

[manfred-brands]

@andrewimcclement That will 'p...' a lot of people which have existing tests with [TestFixture] which are perfectly fine.