game/rings.go had no test coverage at all: not one of the suite's tests
touched wearing a ring, taking one off, choosing a hand, or the ring
contribution to the hunger clock. New game/rings_test.go covers ringOn,
pickRingHand, ringOff, gethand, ringEat and ringNum, plus the ring arm of
things.c dropcheck (dropRing), which is what actually removes a worn ring.
17 tests, 44 subtests; package coverage 53.7% -> 56.2%. No game code
changes.
Every expected value is transcribed from the C reference on origin/c-master
(rings.c, rogue.h, things.c) and quoted in the file, rather than from what
the port currently returns. No divergence from C was found.
ringEat is the reason this matters most: it feeds daemons.c's hunger clock,
so a wrong entry is a slow, silent drift in when the hero starves. All
fourteen ring kinds are pinned to C's uses[] table, both hands. The three C
subtleties are handled explicitly: a negative uses[] entry is a one-in-n
chance of a single unit and not a literal cost; R_DIGEST then flips the
sign, so slow digestion returns 0 or -1; and ring_num's switch closes with
the otherwise macro (rogue.h 53: break;default), so its four labels fall
through to one sprintf and every other kind returns "" from a default arm.
The chance rings are checked by snapshotting the generator, calling
ringEat, and replaying C's own expression from the identical state, which
pins the one-in-n denominator, the sign flip and the fact that exactly one
rnd call is spent; a frequency check over 4000 trials backs it. The
non-negative entries assert the opposite, that the generator is untouched,
because C never reaches rnd on that path and a stray call there would
desynchronise the game's RNG stream from C's.
Scripted hand answers carry an abort tail (a space for the reprompt's
--More--, then ESCAPE) so that a port which stopped accepting a key fails
on its assertion instead of looping forever on the headless terminal's
filler input. The "only one hand free" cases script the wrong hand key on
purpose: a port that prompted anyway would consume it and land the ring on
the wrong side.
Mutation-proved with 23 mutations, each reverted, each failing its own test
and only its own. All fourteen kinds are exercised; the eleven with no
wear-time effect in C are documented at the foot of the file as
deliberately not given a wear/remove test, and ring_off's unreachable "not
wearing such a ring" arm is documented as unreachable.
