Before:

After:

Algorithm Description:

Each time a file is opened or edited, it checks for test methods in the file and uses TestMethodController.setTestMethods to create annotations that use the RunDebugTestGutterAction.java action to execute the test method.

Peculiarities of implementation:

• The implementation was done by analogy with the implementation of annotations for java (ComputeTestMethodsImpl.java).

• Due to the fact that I have not found an analog of EditorAwareJavaSourceTaskFactory for php, I decided to make a binding to the event of getting the focus of the editor tab and changes in the edited document.
  The php project opening hook seemed to me to be a less appropriate place to register a listener. Since events are handled for each editor tab regardless of the project and file type, I made the ComputeTestMethodAnnotations class a singleton to avoid having to register the listener multiple times if multiple php projects are open.

• TestMethodController.setTestMethods implements all the work of creating an annotation to run a test method.
  Apparently, this method should update the list of annotations at each call of this method, when the passed collection of methods changes. Вut I didn't manage to achieve correct work in this case. While debugging the ComputeTestMethodsImpl.java class for java, I noticed that the method is called twice: first for an empty collection,
  then for a collection with new computed methods.
  So I made the method call first with the empty collection, to clear the annotation list, then already with the method collection.

• The algorithm of searching for test methods was made by analogy as in the implementation of action for launching a test method for execution from the context menu of the editor.