While I work on the smaller reproduction, some information that may help --

It looks like in NUnit.AssemblyHooks.template.cs, the FixtureLifeCycle is set to InstancePerTestCase.

I'm not sure if this is intended, but it conflicts with the NUnit default, which according to the docs is SingleInstance.

Because this assembly-level attribute is set, I think my tests are picking up the non-default behavior and NUnit is therefore expecting them to adhere to the static constraint.

You can find a basic reproduction at https://github.com/sct-software/Reqnroll-379-reproduction

There are two tags -- the commit prior to the issue being introduced, and then adding Reqnroll.NUnit which introduces the issue. The current commit on the main branch has the issue reproduced.

An quick workaround for this is setting [FixtureLifeCycle(LifeCycle.SingleInstance)] on our non-Reqnroll test class -- this resolved the issue.

So I'd suggest the outcome of this issue could be:

• A change in the assembly level setting to the NUnit default of SingleInstance
• Or, a note on https://docs.reqnroll.net/latest/integrations/nunit.html describing this behavior, what it might cause, and how users might want to mitigate it.

I'm happy to do a PR for either of those.

Thanks for the good analysis and reproduction 🙂 .

This change was introduced when we supported parallel execution at the scenario/method level (see #277).

We could fix this by adding the FixtureLifeCycle to each generated class instead of doing it globally.

Sounds good, I'll do the PR for it, today if I can. Not mad if anyone beats me to it :)