Engine Parallel Test Execution

DRAFT

The NUnit test engine is able to offer a certain degree of parallelization by running the tests in each test assembly in a different Process. If tests are already split across multiple assemblies, this is the simplest way to improve performance through parallel execution.

Note: This is a separate facility from Framework Parallel Test Execution although the two may be used concurrently.

Process Model

NUnit 3 uses the ProcessModel enumeration to specify how assemblies are split across processes. The ProcessModel for a run may specified either on the console command-line or in the NUnit project file.

As in NUnit V2, three values are defined:

• ProcessModel.Single causes all tests to be run within the NUnit process itself.
• ProcessModel.Separate loads and runs all the tests in a single separate process.
• ProcessModel.Multiple loads and runs each test assembly in a separate process.

In NUnit 3, if ProcessModel.Multiple is used, the processes are executed in parallel. This is also the default if the ProcessModel is not specified.