Hi, Shilpa. When you check
All Tests, that creates a run configuration that will always include all tests even as things evolve over time. Uncheck that and it should show all test classes and methods from which you can select the subset you wish to include. If you want to run a specific test class or method, you can also right-click on the class/method name and click any of the following context menu options:
Those actions are also available in the gutter to the left of the class/method:
and can be invoked using Alt+Enter (Windows/Linux) or Opt+Enter (Mac).
Please let me know if that doesn't provide what you need.
Regards,
Scott Wells