Scope NUnit parallelization to generated classes instead of assembly-level

[SeanKilleen]

🤔 What's changed?

• Removed assembly-wide attribute declaring parallelization to be InstancePerTestCase (not the NUnit default)
• Add the attribute to the generated classes.

⚡️ What's your motivation?

Fixes #379

🏷️ What kind of change is this?

• 🐛 Bug fix (non-breaking change which fixes a defect)

♻️ Anything particular you want feedback on?

📋 Checklist:

• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "[vNext]" section of the CHANGELOG, linking to this pull request & included my GitHub handle to the release contributors list.

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This text was originally taken from the template of the Cucumber project, then edited by hand. You can modify the template here.

[SeanKilleen]

(This is still in progress, just FYI. I wanted to see how the build responded to the initial change.)

[obligaron]

Tip: Here is the code that generates the NUnit specific attributes for a class

Reqnroll/Reqnroll.Generator/UnitTestProvider/NUnit3TestGeneratorProvider.cs

Lines 69 to 73 in 49a023c

	public void SetTestClass(TestClassGenerationContext generationContext, string featureTitle, string featureDescription)
	{
	CodeDomHelper.AddAttribute(generationContext.TestClass, TESTFIXTURE_ATTR);
	CodeDomHelper.AddAttribute(generationContext.TestClass, DESCRIPTION_ATTR, featureTitle);
	}

This code generates

    [NUnit.Framework.TestFixtureAttribute()]
    [NUnit.Framework.DescriptionAttribute("Calculator")]

If you want to add the FixtureLifeCycle attribute to each class, you will probably need to change this.

Hope this helps. 🙂