diff --git a/tests/run.lua b/tests/run.lua
index 0139363..007b45d 100644
--- a/tests/run.lua
+++ b/tests/run.lua
@@ -11893,6 +11893,179 @@ function tests.gameCastSpellOnlyEmitsNoiseOnASuccessfulCastNeverOnAFailedOne()
     game:castSpell("missile", rat)
   end
   eq(bystander.awareness, Stealth.DORMANT, "two hundred failed casts for lack of mana never make a sound")
+
+  game.player.mana = 999
+  local stirred = false
+  for _ = 1, 200 do
+    rat.hp = rat.maxHp
+    game:castSpell("missile", rat)
+    if bystander.awareness ~= Stealth.DORMANT then stirred = true; break end
+  end
+  ok(stirred, "a spell that actually goes off is loud enough to eventually stir a nearby bystander")
+end
+
+function tests.gameDigEmitsNoiseFromTheStruckCellEvenThoughItStartsUnwalkable()
+  local game = stagedGame(1, arena(21, 11), 3, 6)
+  game.level.map:set(4, 6, Tiles.WALL)
+  game.player.pick = Items.pick("miner's pick", 20)
+  local bystander = Monsters.create(Monsters.byKey.orc, 1, 9, 6, 1)
+  bystander.awareness = Stealth.DORMANT
+  game.level.entities = { bystander }
+  local stirred = false
+  for _ = 1, 200 do
+    game:dig(1, 0)
+    if bystander.awareness ~= Stealth.DORMANT then stirred = true; break end
+    if not game.player.pick then game.player.pick = Items.pick("miner's pick", 20) end
+    if game.level.map:get(4, 6) == Tiles.FLOOR then game.level.map:set(4, 6, Tiles.WALL) end
+  end
+  ok(stirred, "the racket of a pick striking solid rock still carries even though the struck cell starts unwalkable")
+end
+
+function tests.diseaseInfectSeedsIncubationAndRefusesToStackASecondInfection()
+  local host = { name = "dummy", hp = 20 }
+  ok(Disease.infect(host, Disease.PARASITES), "infecting a clean host succeeds")
+  ok(Disease.isInfected(host), "the host now carries an infection")
+  eq(host.disease.incubation, Disease.defs[Disease.PARASITES].incubation, "incubation starts at the affliction's own listed value")
+  eq(host.disease.stage, 0, "a freshly seeded infection has not erupted yet")
+  ok(not Disease.infect(host, Disease.ROT), "a second affliction cannot take hold while one is already active")
+  eq(host.disease.key, Disease.PARASITES, "the original infection is left completely untouched by the refused attempt")
+end
+
+function tests.diseaseUnknownKeyNeverInfects()
+  local host = { name = "dummy", hp = 20 }
+  ok(not Disease.infect(host, "swamp fever"), "an unrecognised affliction key never takes hold")
+  ok(not Disease.isInfected(host), "the host stays clean")
+end
+
+function tests.diseaseIsInfectedAndHasEruptedTrackIncubationVsActiveStageSeparately()
+  local host = { name = "dummy", hp = 20 }
+  Disease.infect(host, Disease.ROT)
+  ok(Disease.isInfected(host), "an incubating host already counts as infected")
+  ok(not Disease.hasErupted(host), "but has not yet erupted while incubation is still counting down")
+  host.disease.stage = 1
+  ok(Disease.hasErupted(host), "once staged past zero the infection counts as erupted")
+end
+
+function tests.diseaseTickCountsIncubationDownInSilenceThenErupts()
+  local host = { name = "dummy", hp = 20 }
+  Disease.infect(host, Disease.PARASITES)
+  local incubation = Disease.defs[Disease.PARASITES].incubation
+  for i = 1, incubation - 1 do
+    local line = Disease.tick(host)
+    eq(line, nil, "each turn still incubating produces no visible symptom")
+    eq(host.disease.stage, 0, "the infection has not erupted yet at turn " .. i)
+  end
+  local eruptionLine = Disease.tick(host)
+  ok(contains(eruptionLine, "breaks out"), "the turn incubation runs out, the eruption is reported")
+  eq(host.disease.stage, 1, "the infection is now active at stage one")
+end
+
+function tests.diseaseTickDealsStagePotencyThroughResistancesAndEscalatesOnItsFixedSchedule()
+  local host = { name = "dummy", hp = 1000 }
+  Disease.infect(host, Disease.ROT)
+  host.disease.stage = 1
+  host.disease.sinceStage = 0
+  local def = Disease.defs[Disease.ROT]
+  local hpBefore = host.hp
+  Disease.tick(host)
+  eq(host.hp, hpBefore - def.stagePotency[1], "a stage-one tick deals exactly that stage's listed potency")
+  for _ = 2, def.stageTurns - 1 do
+    Disease.tick(host)
+  end
+  eq(host.disease.stage, 1, "the stage holds steady right up until its full window has elapsed")
+  local escalationLine = Disease.tick(host)
+  ok(contains(escalationLine, "worsens"), "the tick that completes the window reports the escalation")
+  eq(host.disease.stage, 2, "the infection has moved on to stage two")
+  eq(host.disease.sinceStage, 0, "the new stage starts its own window fresh")
+end
+
+function tests.diseaseTickNeverEscalatesPastTheTopStage()
+  local host = { name = "dummy", hp = 1000 }
+  Disease.infect(host, Disease.PLAGUE)
+  host.disease.stage = Disease.MAX_STAGE
+  host.disease.sinceStage = 0
+  local def = Disease.defs[Disease.PLAGUE]
+  for _ = 1, def.stageTurns * 3 do
+    Disease.tick(host)
+  end
+  eq(host.disease.stage, Disease.MAX_STAGE, "the top stage never escalates any further, however long it lingers")
+end
+
+function tests.diseaseAnImmuneHostTakesNoDamageButStillEscalatesOnSchedule()
+  local host = { name = "dummy", hp = 1000, resist = { poison = Resistances.IMMUNE } }
+  Disease.infect(host, Disease.ROT)
+  host.disease.stage = 1
+  host.disease.sinceStage = 0
+  local def = Disease.defs[Disease.ROT]
+  local hpBefore = host.hp
+  for _ = 1, def.stageTurns - 1 do
+    local line = Disease.tick(host)
+    eq(line, nil, "an immune host takes no damage, so a plain tick has nothing to report")
+  end
+  eq(host.hp, hpBefore, "an immune host never loses hp to the infection at all")
+  local escalationLine = Disease.tick(host)
+  ok(contains(escalationLine, "worsens"), "immunity blocks the damage but not the clock - the stage still worsens on schedule")
+end
+
+function tests.diseaseCureLiftsAnInfectionAtAnyStageAndReportsFalseWhenThereWasNothingToLift()
+  local host = { name = "dummy", hp = 20 }
+  eq(Disease.cure(host), false, "curing a clean host reports nothing was lifted")
+  Disease.infect(host, Disease.PARASITES)
+  ok(Disease.cure(host), "curing an incubating infection succeeds")
+  ok(not Disease.isInfected(host), "the host is clean again")
+  Disease.infect(host, Disease.PLAGUE)
+  host.disease.stage = 3
+  ok(Disease.cure(host), "curing works exactly the same on a fully erupted top-stage infection")
+  ok(not Disease.isInfected(host), "the host is clean again regardless of how far the infection had progressed")
+end
+
+function tests.diseaseStagePotencyIsZeroWhileIncubatingOrUninfected()
+  local host = { name = "dummy", hp = 20 }
+  eq(Disease.stagePotency(host), 0, "an uninfected host has no stage potency at all")
+  Disease.infect(host, Disease.ROT)
+  eq(Disease.stagePotency(host), 0, "a still-incubating infection has not erupted into any potency yet")
+  host.disease.stage = 2
+  eq(Disease.stagePotency(host), Disease.defs[Disease.ROT].stagePotency[2], "an erupted stage reports its own listed potency")
+end
+
+function tests.gameMonsterMeleeCanInfectThePlayerViaABiteCarryingSpeciesButNeverStacksASecondInfection()
+  local game = stagedGame(1, arena(21, 11), 3, 6)
+  local rat = Monsters.create(Monsters.byKey.rat, 1, 4, 6, 1)
+  game.level.entities = { rat }
+  game.player.hp = 10000
+  game.player.maxHp = 10000
+  local infected = false
+  for _ = 1, 400 do
+    game:monsterMelee(rat)
+    if Disease.isInfected(game.player) then infected = true; break end
+  end
+  ok(infected, "enough bites from a parasite-carrying species eventually infect the player")
+  eq(game.player.disease.key, Disease.PARASITES, "the player caught exactly the species' own carried affliction")
+  local firstIncubation = game.player.disease.incubation
+  for _ = 1, 50 do
+    game:monsterMelee(rat)
+  end
+  ok(game.player.disease.incubation <= firstIncubation, "further bites while already sick never restart or stack a second infection")
+end
+
+function tests.gameMonsterMeleeNeverInfectsFromASpeciesWithNoBiteDisease()
+  local game = stagedGame(1, arena(21, 11), 3, 6)
+  local goblin = Monsters.create(Monsters.byKey.goblin, 1, 4, 6, 1)
+  eq(goblin.biteDisease, nil, "a goblin carries no disease of its own to begin with")
+  game.level.entities = { goblin }
+  game.player.hp = 10000
+  game.player.maxHp = 10000
+  for _ = 1, 400 do
+    game:monsterMelee(goblin)
+  end
+  ok(not Disease.isInfected(game.player), "four hundred goblin bites never infect anyone, since goblins carry nothing to catch")
+end
+
+function tests.gameEndPlayerTurnTicksThePlayersDiseaseAndLogsItsEruption()
+  local game = stagedGame(1, arena(21, 11), 3, 6)
+  Disease.infect(game.player, Disease.PARASITES)
+  local incubation = Disease.defs[Disease.PARASITES].incubation
+  for _ = 1, incubation - 1 do
 end
 
 local order = {