Tests are an important part of modern software development practice. Writing tests for your code helps you have confidence that your project works as expected as it scales in size and complexity. Unity provides the Unity Test Framework package to help you write and run tests for your C# code.
The package integrates and extends the C# test framework NUnit, adding custom Unity functionality is a tool that allows you to test your code in both Edit mode and Play mode, and also on target platforms such as Standalone, Android, or iOS. The Test RunnerThe Test Framework package (formerly called the Test Runner) is a Unity tool that tests your code in both Edit mode and Play mode, and also on target platforms such as Standalone, Android, or iOS. More info
See in Glossary window is built into the Editor and works similarly to test runners in IDEs like Visual Studio.
For more information on other versions of the Test Framework package, refer to the com.unity.test-framework page.