Workflow: How to create a new test assembly

Unity Test Framework looks for a test inside any assembly that references NUnit. We refer to such assemblies as Test Assemblies. Play Mode and Edit Mode tests need to be in separate assemblies.

The Test Runner UI helps you set up TestAssemblies:

1. Select the Assets folder in your Project window.
2. Open the Test Runner window (menu: Window > General > Test Runner).
3. In the Test Runner window, the EditMode tab should be selected by default. Click Create EditMode Test Assembly Folder.

This creates a Tests folder in your project Assets with a corresponding .asmdef file with the required references. You can change the name of the new Assembly Definition and press Enter to accept it.

Click on the assembly definition file to inspect it in the Inspector window. You'll see that it has references to nunit.framework.dll under Assembly References, and to UnityEngine.TestRunner and UnityEditor.TestRunner under Assembly Definition References. This tells Unity Test Framework that this is a test assembly.

The checkbox selections under Platforms determine which platforms the test assembly can run on. Assemblies created through the Test Runner target the Editor only by default. Any Platform or a specific platform other than Editor makes the tests you add run in Play Mode by default.

Note: The UnityEditor.TestRunner reference is only available for Edit Mode tests.

Reference other assemblies in your Test Assemblies

To reference other assemblies from your Test Assemblies:

1. Create your Test Assembly as described above.
2. Create an Assembly Definition for the scripts you want to reference, refer to Create an Assembly Definition asset.
3. Add a reference to the Assembly Definition created in Step 2 to your Test Assembly, refer to Referencing another assembly.

Additional resources

Refer to the Unity Manual page on Assembly definitions for more detail on using Assembly Definition files to manage references.