view.love/Manual_tests.md

I care a lot about being able to automatically check any property about my program before it ever runs. However, some things don't have tests yet, either because I don't know how to test them or because I've been lazy. I'll at least record those here.

Startup: - terminal log shows unit tests running

Initializing settings: - delete app settings, start; window opens running the text editor - quit while running the text editor, restart; window opens running the text editor in same position+dimensions - quit while editing source (color; no selection), restart; window opens editing source in same position+dimensions - start out running the text editor, move window, press ctrl+e twice; window is running text editor in same position+dimensions - start out editing source, move window, press ctrl+e twice; window is editing source in same position+dimensions - no log file; switching to source works

Code loading:

• run love with directory; text editor runs

• run love with zip file; text editor runs

• How the screen looks. Our tests use a level of indirection to check text and graphics printed to screen, but not the precise pixels they translate to.

  • where exactly the cursor is drawn to highlight a given character
  • analogously, how a shape precisely looks as you draw it

• start out running the text editor, press ctrl+e to edit source, make a change to the source, press ctrl+e twice to return to the source editor; the change should be preserved.

Other compromises

Lua is dynamically typed. Tests can't patch over lack of type-checking.

• All strings are UTF-8. Bytes within them are not characters. I try to label byte offsets with the suffix _offset, and character positions as _pos. For example, string.sub should never use a _pos to substring, only an _offset.

• Some ADT/interface support would be helpful in keeping per-line state in sync. Any change to line data should clear line fragments and screen_line_starting_pos.

• Some inputs get processed in love.textinput and some in love.keypressed. Several bugs have arisen due to destructive interference between the two for some key chord. I wish I could guarantee that the two sets are disjoint. But perhaps I'm not thinking about this right.

• Like any high-level language, it's easy to accidentally alias two non-scalar variables. I wish there was a way to require copy when assigning.

• I wish I could require pixel coordinates to integers. The editor defensively converts input margins to integers.

• My test harness automatically runs test_* methods -- but only at the top-level. I wish there was a way to raise warnings if someone defines such a function inside a dict somewhere.