c# - How to run unit tests (MSTest) in parallel?

Question

I am looking for ways to run test suites in parallel.

I am aware of .testrunconfig setting. This allows you to multiplex on the number of CPUs.

I want to run 1000 tests in parallel. This makes sense because I am testing a web service, so 90% of the time spent in a test is waiting for the service to respond.

Any ideas on how to pull this off ? The tests are written for VS, but I am open to running them outside of VS.

Later edit: the Visual Studio test team have added this in VS 2015 Update 1. See Mark Sowul's answer bellow.

Answer 1

Most of the answers on this page forget to mention that MSTest parallelizes tests in separate assemblies. You have to split your unittests into multiple .dll's to paralelize it.

But! The recent version - MSTest V2 - now CAN parallelize "in-assembly" (yay!) you just need to install a couple of nuget packages in your test project - TestFramework and TestAdapter - like described here https://blogs.msdn.microsoft.com/devops/2018/01/30/mstest-v2-in-assembly-parallel-test-execution/

And then simply add this to your test project

[assembly: Parallelize(Workers = 4, Scope = ExecutionScope.ClassLevel)]

EDIT: You can also disable parallel execution for a specific test using [DoNotParallelize] on a test method.