Suppose you have a new Main class, with 2 methods a and b
Pressing Control-Shift-T allows us to create new test class and create stubs for both methods

Ok, now if i add 1 more method c, i’d like to add a test for it in already existing MainTest class
How can this be done please using IDEA? Control-Shift-T does not work as it attempts to create an already existing test class.
This feature is not implemented yet, please vote for the linked request.