Second wave of pre-Phase-3 test coverage. The #55 round picked off the
easy decision-logic helpers; this round covers the three highest-impact
helpers that escaped the first sweep.
Three new test classes appended to tests/test_ai_pure.py:
- TestTokenTracker (11 tests)
Pins the load-bearing #44 fix: budget_exceeded() must use last_input
(the most recent call's context size) NOT cumulative input, because
each turn's input_tokens already includes the full message history.
Tests assert: cumulative-input far above budget does NOT trip the
gate when last_input stays small; reset_loop() preserves grand
totals; the boundary is strict > not >=.
- TestSynthesizeFromCache (5 tests)
The synthesis fallback fires only when _run_synthesis exhausts its
max_turns, which almost never happens in normal runs — exactly the
kind of code that silently rots. Tests assert: empty cache returns
the incomplete-message brief and empty detailed; single dir entry
produces a markdown line; multi-entry detailed contains all entries;
empty-summary entries are skipped; file entries alone do not satisfy
(the function reads dir entries only).
- TestDiscoverDirectories (9 tests)
The leaves-first walk drives the entire dir-loop iteration order
and is the foundation of the cache reuse story. Tests assert:
empty target returns target only; nested trees come back leaves-
first; .git / __pycache__ / node_modules / *.egg-info excluded;
custom --exclude honored; hidden dirs excluded by default; show_
hidden=True includes them but does not override the skip list.
PLAN.md: added Phase 2.7 (#56✅) and Phase 2.8 (#55✅, #70) entries
to the implementation order, and removed the now-stale Phase 3.4 (#56)
and Background chore (#55) sections that were displaced by the
pre-Phase-3 cleanup pattern.
Verification: 234 tests pass (209 prior + 25 new).
