Problem: fc4a47a changed the priority display format from '! ' to
'[N] ' in views.lua and diff.lua but left two existing test
assertions and their descriptions using the old format, causing
both to fail.
Solution: update the input line in diff parse_buffer test, update
the expected string and description names in views category_view
test, and rename the diff.apply description to match the new idiom.
Problem: several critical code paths had zero test coverage —
parse.resolve_date (relative date resolution), store.snapshot
(foundation of the undo stack), and the diff.apply invariant that
unchanged tasks do not get their modified timestamp bumped. The
diff.apply due/priority clearing paths were also untested.
Solution: add six targeted test blocks across parse_spec, store_spec,
and diff_spec: resolve_date happy/failure paths, parse.body with
relative due tokens, snapshot copy-semantics and deleted-task
exclusion, diff unchanged-modified invariant, due cleared on removal,
priority cleared on ! removal.
Problem: need test coverage for core data operations, inline
metadata parsing, and buffer diff algorithm.
Solution: add busted specs for store CRUD, round-trip
preservation, parse body/command_add with configurable date
syntax, and diff create/delete/update/copy/move operations.
