Unit tests for argument parsing; one Run per --email end-to-end test #205

Parent

#174

What to build

Test argument parsing where it lives, not through whole Runs. Argument parsing has no unit tests today, so every case is checked by running the real binary end to end. For example, one test does six full Runs to cover the positions --email and email can take, and another does three for bare-flag and address handling. Add unit tests for argument parsing that cover every case those loops cover: flag position, a bare flag against an address, the issue URL never taken as an address, and a merge goal before and after. Then cut each of those end-to-end tests down to one Run that shows the parsed arguments actually reach the Run notification.

Acceptance criteria

• Unit tests of argument parsing cover every case the --email looping end-to-end tests cover today
• Each of those end-to-end tests runs the binary once
• No behavior the suite checked before is left untested
• The PR reports the run_notification binary's time before and after
• The full suite passes

Blocked by

• Record the test suite baseline and make debug builds cheaper #202