test code notation with break

Start by reviewing the existing debug_code test framework usage and the two proposed notations: comments on source lines or markers beside line numbers. Compare both with the existing break commands and debugger method, then define how tests should translate the chosen notation into breakpoints and how completion will be verified.

Just idea.

Now we need to set breakpoints with break commands on tests like:

    def program
      <<~RUBY
       1| def foo a
       2|   b = a + 1  # break
       3| end
       4| x = 1        # break
       5| x = 2
       6| x = 3
      RUBY
    end

    def test_foobar
      debug_code program do
        type 'break 2'
        type 'break 4'

On this code, line 2 and 4 is breakpont, and using 2 break commands. On the other hands, if we use IDE we can set breakpoints on a code (with editor's support). So we can write breakpoints on the code.

IDEA1: Use comment on the line.

      <<~RUBY
       1| def foo a
       2|   b = a + 1  # break
       3| end
       4| x = 1        # break
       5| x = 2
       6| x = 3
      RUBY

and issues two break commands by the test framework.

IDEA2: Check on the left of line number:

      <<~RUBY
       1| def foo a
      *2|   b = a + 1
       3| end
      *4| x = 1
       5| x = 2
       6| x = 3
      RUBY

and issues two break commands by the test framework.

Of course we can write debugger method, but it can be different from normal break points, so it should be supported separately.