NUnit - prevent 2 specific classes from running in parallel

Question

I have a test project with many tests and many test classes. Most of them can run in parallel without any problem, but there are 2 specific test classes whose tests access a certain file, and therefore cannot run in parallel.

I guess that if I put [Parallelizable(ParallelScope.All)] on all other classes and [Parallelizable(ParallelScope.None)] on these 2 classes, then it should be safe, but AFAIU it also means that these 2 classes won't run in parallel with any other class, which is not what I want, as it's not the most efficient solution.

Is there any other, more efficient way to achieve that?

Answer 1

Few points to consider:

• [Parallelizable] or [NonParallelizable] may be specified on multiple levels of the tests, with lower-level specifications overriding higher ones to a certain degree.
• It is important to note that a parallel or non-parallel specification only applies at that level where it appears and below. It cannot override the settings on higher-level tests.

For your situation, you can create Parallel class with non-parallel methods: The methods within this class run sequentially, usually on the same thread that ran the class one-time setup, but may actually be running in parallel with other, unrelated methods from other classes. So your class can be:

[Parallelizable(ParallelScope.All)]
public class MyClass1 
{
    [NonParallelizable]
    [Test]
    public void Test1()
    {
    }

    [NonParallelizable]
    [Test]
    public void Test2()
    {
    }
}

[Parallelizable(ParallelScope.All)]
public class MyClass2 //Another class in same Assembly
{
    //methods within this class will run in parallel with other 
    //class methods within same assembly except method Test1 and Test2 of MyClass1
} 

Hope this helps. Details here