diff --git a/tests/run.lua b/tests/run.lua
index f36d937..6581fc3 100644
--- a/tests/run.lua
+++ b/tests/run.lua
@@ -9298,6 +9298,179 @@ function tests.trapDetectedFieldSurvivesSerialization()
   os.remove(path)
   eq(restored.level.traps[1].detected, true, "a trap's detected flag survives a save/load round trip")
 end
+
+function tests.secretsSweepDiscoversAnAdjacentHiddenDoorEventuallyAcrossAHandfulOfSeeds()
+  local discovered = false
+  for seed = 1, 100 do
+    local level = arena(21, 11)
+    level.secretDoors = { { x = 5, y = 5, discovered = false } }
+    if #Secrets.sweep(level, Rng.new(seed), 5, 6) > 0 then discovered = true break end
+  end
+  ok(discovered, "an adjacent secret door is eventually discovered across a handful of seeds")
+end
+
+function tests.secretsSweepNeverDiscoversADoorTwoStepsAway()
+  for seed = 1, 200 do
+    local level = arena(21, 11)
+    level.secretDoors = { { x = 5, y = 5, discovered = false } }
+    eq(#Secrets.sweep(level, Rng.new(seed), 7, 7), 0,
+      "a secret door two steps away is never discovered regardless of the roll")
+  end
+end
+
+function tests.secretsSweepNeverRediscoversAnAlreadyDiscoveredDoor()
+  local level = arena(21, 11)
+  level.secretDoors = { { x = 5, y = 5, discovered = true } }
+  for seed = 1, 50 do
+    eq(#Secrets.sweep(level, Rng.new(seed), 5, 5), 0, "an already-discovered door is never swept again")
+  end
+end
+
+function tests.secretsSweepOpensTheWallIntoAPlainClosedDoorOnDiscovery()
+  local level = arena(21, 11)
+  level.map:set(5, 5, Tiles.WALL)
+  level.secretDoors = { { x = 5, y = 5, discovered = false } }
+  local found
+  for seed = 1, 100 do
+    local door = Secrets.sweep(level, Rng.new(seed), 5, 6)[1]
+    if door then found = door break end
+  end
+  ok(found ~= nil, "the door is eventually discovered")
+  eq(found.discovered, true, "the discovered door's own flag is flipped")
+  eq(level.map:get(5, 5), Tiles.DOOR_CLOSED, "the wall tile becomes a plain closed door once discovered")
+end
+
+local function orthogonalNeighbours(x, y)
+  return { { x + 1, y }, { x - 1, y }, { x, y + 1 }, { x, y - 1 } }
+end
+
+local function reachableFrom(map, fromX, fromY, x, y)
+  return Astar.find(map, fromX, fromY, x, y, function(cx, cy)
+    return not map:isPassable(cx, cy, false)
+  end) ~= nil
+end
+
+function tests.builderOccasionallyPlacesASecretDoorGuardingAGenuinelyUnreachableAlcove()
+  local checked = 0
+  for seed = 1, 200 do
+    local level = Builder.build(3, Rng.new(seed), {})
+    if #level.secretDoors == 1 then
+      checked = checked + 1
+      local door = level.secretDoors[1]
+      eq(door.discovered, false, "a freshly built floor's secret door always starts undiscovered")
+      eq(level.map:get(door.x, door.y), Tiles.WALL, "an undiscovered secret door still reads as an ordinary wall")
+
+      -- Exactly one of the door's own orthogonal neighbours is the alcove
+      -- itself: real floor, yet unreachable from the stairs while the door
+      -- between them is still a plain, impassable wall.
+      local alcoveX, alcoveY
+      for _, n in ipairs(orthogonalNeighbours(door.x, door.y)) do
+        local nx, ny = n[1], n[2]
+        if level.map:isWalkable(nx, ny) and not reachableFrom(level.map, level.upX, level.upY, nx, ny) then
+          alcoveX, alcoveY = nx, ny
+        end
+      end
+      ok(alcoveX ~= nil, "seed " .. seed .. ": the secret door hides a genuinely unreachable alcove cell")
+      if alcoveX then
+        level.map:set(door.x, door.y, Tiles.DOOR_CLOSED)
+        ok(reachableFrom(level.map, level.upX, level.upY, alcoveX, alcoveY),
+          "seed " .. seed .. ": the same alcove opens up the instant its door is discovered")
+      end
+      if checked >= 10 then break end
+    end
+  end
+  ok(checked > 0, "at least one of the sampled seeds actually places a secret door")
+end
+
+function tests.builderNeverPlacesASecretDoorAboveDepthTwo()
+  for seed = 1, 10 do
+    local level = Builder.build(1, Rng.new(seed), {})
+    eq(#level.secretDoors, 0, "no secret door appears on the first floor")
+  end
+end
+
+function tests.gameEndPlayerTurnEventuallyDiscoversAnAdjacentSecretDoorAcrossAHandfulOfSeeds()
+  local discovered = false
+  for seed = 1, 100 do
+    local game = stagedGame(1, arena(21, 11), 3, 6)
+    game.rng = Rng.new(seed)
+    game.level.map:set(4, 6, Tiles.WALL)
+    game.level.secretDoors = { { x = 4, y = 6, discovered = false } }
+    game:endPlayerTurn()
+    if game.level.secretDoors[1].discovered then
+      local reported = false
+      for _, line in ipairs(game.log:recent(6)) do
+        if contains(line, "hidden door") then reported = true end
+      end
+      ok(reported, "a freshly discovered secret door is reported somewhere in the turn's log lines")
+      eq(game.level.map:get(4, 6), Tiles.DOOR_CLOSED, "the discovered door's tile is a plain closed door")
+      discovered = true
+      break
+    end
+  end
+  ok(discovered, "an adjacent secret door is eventually discovered over a handful of seeded turns")
+end
+
+function tests.secretDoorFieldsSurviveSerialization()
+  local game = Game.new(5)
+  game.level.secretDoors = { { x = 3, y = 3, discovered = false } }
+  local path = os.tmpname()
+  game:save(path)
+  local restored = Game.load(path)
+  os.remove(path)
+  eq(#restored.level.secretDoors, 1, "the secret door list survives a save/load round trip")
+  eq(restored.level.secretDoors[1].discovered, false, "a secret door's discovered flag survives a round trip")
+end
+
+function tests.chestsNewLootAlwaysIncludesGoldAndExactlyOneGearPiece()
+  for seed = 1, 30 do
+    local chest = Chests.new(Rng.new(seed), 3)
+    local goldCount, gearCount = 0, 0
+    for _, item in ipairs(chest.loot) do
+      if item.kind == Items.GOLD then goldCount = goldCount + 1 end
+      if item.kind == Items.WEAPON or item.kind == Items.ARMOR then gearCount = gearCount + 1 end
+    end
+    eq(goldCount, 1, "every chest carries exactly one pile of gold")
+    eq(gearCount, 1, "every chest carries exactly one weapon or armor piece")
+  end
+end
+
+function tests.chestsNewNeverRollsTrappedOnAnUnlockedChest()
+  local sawLockedTrapped, sawLockedUntrapped = false, false
+  for seed = 1, 100 do
+    local chest = Chests.new(Rng.new(seed), 3)
+    ok(chest.locked or not chest.trapped, "an unlocked chest is never also trapped")
+    if chest.locked and chest.trapped then sawLockedTrapped = true end
+    if chest.locked and not chest.trapped then sawLockedUntrapped = true end
+  end
+  ok(sawLockedTrapped, "a locked chest eventually rolls trapped across a handful of seeds")
+  ok(sawLockedUntrapped, "a locked chest eventually rolls untrapped across a handful of seeds")
+end
+
+function tests.chestsIsLockedIsTrueForALockedUnopenedChestAndFalseOnceOpened()
+  local chest = { locked = true, trapped = false, opened = false, loot = { Items.gold(5) } }
+  eq(Chests.isLocked(chest), true, "a locked, unopened chest reports locked")
+  chest.opened = true
+  eq(Chests.isLocked(chest), false, "an opened chest never reports locked, whatever its own flag says")
+end
+
+function tests.chestsOpenGrantsEveryLootItemAndEmptiesTheChest()
+  local player = { inventory = {} }
+  local chest = { locked = false, trapped = false, opened = false, loot = { Items.gold(5), Items.potionOf("heal") } }
+  local success, line = Chests.open(player, chest)
+  ok(success, "opening an unlocked chest succeeds")
+  eq(#player.inventory, 2, "every loot item lands in the inventory")
+  eq(chest.opened, true, "the chest is marked opened")
+  eq(#chest.loot, 0, "the chest's own loot list is emptied")
+  ok(contains(line, "open"), "the opening is reported")
+end
+
+function tests.chestsOpenRefusesAnAlreadyEmptiedChest()
+  local player = { inventory = {} }
+  local chest = { locked = false, trapped = false, opened = true, loot = {} }
+  local success, line = Chests.open(player, chest)
+  eq(success, false, "opening an already-emptied chest fails")
+  eq(#player.inventory, 0, "nothing is granted from an already-emptied chest")
 end
 
 local order = {