The Unity Test Framework package (formerly the “Unity Test Runner”) is a tool that tests your code in both Edit mode and Play mode, and also on target platforms such as Standalone, Android, or iOSApple’s mobile operating system. More info
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As of Unity version 2019.2, this tool has been available in the Unity Test Framework package, which you can download in the Unity Package Manager.
For more information on available versions, see the com.unity.test-framework page.