NUnit running classes in parallel

Question

Iam a little bit confused about the Parallel attribute of nunit:

Say i have 3 Classes each filled with some tests:

ClassA
    - Test1
    - Test2
    - Test3
ClassB
    - Test1
ClassC
    - Test1
    - Test2

I would like to run Every Test in ClassA and ClassB in parallel (i dont care about order )

I also would like to run ClassC while ClassA and ClassB are running, but in this class i want to keep the order in which i specified the tests

So my question is how should i set the attributes to get a behaviour like this?

I checked the docu https://github.com/nunit/docs/wiki/Framework-Parallel-Test-Execution but iam still confused

Charlie Charlie · Accepted Answer · 2018-11-20T18:17:37

Starting simple...

If you do nothing with ParallelizableAttribute then nothing runs in parallel. :-)
If you add Parallelizable to each fixture, then the three fixtures will run in parallel, but the individual tests will not. That is, up to three things can be running at one time, one from each class.
If you add [Parallelizable(ParallelScope.Fixtures)] at the assembly level, the effect is the same as (2). You should only do this if almost all of your fixtures will successfully run in parallel, in which case you would mark those that can't as [NonParallelizable]. My experience in helping people is that too many people do this without realizing that their tests may not always run correctly in parallel when not written to do so. Starting out, it's safest to default to non-parallel and only add it when it works for you.
Starting with (2), change the attribute on A and B to [Parallelizable(ParallelScope.All)] or [Parallelizable(ParallelScope.Self + ParallelScope.Children). I like the longer form because it's much clearer to readers as to what it does. This will have exactly the effect that you want.

One more note: you should probably make sure that any fixture in which you specify the order of tests does not run in parallel. NUnit let's you specify both parallel and order without error. In that case, it simply starts the tests in the order you give, but that may not be what you intended. 4.

NUnit running classes in parallel

1 Answers