snap.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.

Initializing settings:

• delete app settings, start with a filename; window opens with cursor at top of file

• run with absolute file path; quit; restart; window opens in same position+dimensions

• run with relative file path; quit; switch to new directory; restart without a filename; window opens running the same file in same position+dimensions

• run with a filename on commandline, scroll around, quit; restart without a filename; window opens in same position+dimensions

• run with a filename on commandline, scroll around, quit; restart with same filename; window opens in same position+dimensions

• run with a filename on commandline, scroll around, quit; restart with new filename; window opens new filename with cursor up top

• run editor, scroll around, move cursor to end of some line, quit; restart with new filename; window opens in same position+dimensions

• run with an untested version of LÖVE. Error message pops up and waits for a key. The app attempts to continue, and doesn't receive the key.

• run with a LÖVE v12 release candidate. No errors; it is a supported version. All tests pass.

• create a couple of spuriously failing tests. Run with an untested version of LÖVE. Error message includes message about untested version.

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

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, only an _offset.

• Some ADT/interface support would be helpful in keeping per-line state in sync. Any change to line data should clear the derived line property 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 be 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.