test(nx-mods): lock zip and chord edge regressions

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/engine/game_display_chord_test.lua

@@ -114,6 +114,25 @@ Game:gamepadpressed(joySelectDown, "y")
 eq(digits[1], "5", "Select via isGamepadDown(back) + Y -> 5")
 eq(#padForwarded, 0, "isGamepadDown Select chord does not forward face")
 
+-- Edge: every chord face without Select must not cycle (NXMOD-09)
+GamepadMap._setForceNXForTests(false)
+for _, btn in ipairs({ "a", "b", "y", "x", "leftshoulder" }) do
+  Input:init()
+  resetSpies()
+  Game:gamepadpressed(joy, btn)
+  eq(#digits, 0, "edge: no cycle without Select for " .. btn)
+  eq(#padForwarded, 1, "edge: " .. btn .. " still reaches Input without Select")
+  check(not wroteOptions, "edge: no options write without Select for " .. btn)
+end
+
+-- Edge: Select alone (no face) does not synthesize a digit
+holdSelect()
+resetSpies()
+-- pressing back again while held is not a display chord partner
+Game:gamepadpressed(joy, "back")
+eq(#digits, 0, "edge: Select alone does not fire a display digit")
+eq(#padForwarded, 1, "edge: Select alone still forwards to Input")
+
 GamepadMap._setForceNXForTests(false)
 Game.keypressed = origKeypressed
 Input.gamepadpressed = origPad

tests/engine/input_display_chord_test.lua

@@ -40,4 +40,10 @@ eq(GamepadMap.displayChordDigit("x"), "6", "NX X -> key 6")
 eq(GamepadMap.displayChordDigit("leftshoulder"), "7", "NX L -> key 7")
 GamepadMap._setForceNXForTests(false)
 
+-- Edge: map alone never invents a digit for non-chord faces (NXMOD-09 map half)
+for _, btn in ipairs({ "guide", "leftstick", "rightstick", "lefttrigger" }) do
+  eq(GamepadMap.displayChordDigit(btn), nil,
+    "edge: unmapped " .. btn .. " is not a display digit")
+end
+
 T.finish()

tests/rom_importer_nx_mods_inbox_test.lua

@@ -119,6 +119,19 @@ for _, path in ipairs(roms) do
 end
 eq(#roms, 0, "ROM scanInbox finds no zip-only inbox entries")
 
+-- Edge: ROM inbox with .gb alongside .zip still ignores zip (spec edge)
+ri = freshImporter()
+love.filesystem.write("imports/cart.gb", string.rep("G", 16))
+love.filesystem.write("imports/sidecar.zip", "NOTAROM")
+roms = ri:scanInbox(ri.ready)
+local sawGb, sawZip = false, false
+for _, path in ipairs(roms) do
+  if path:lower():match("%.zip$") then sawZip = true end
+  if path:lower():match("%.gb$") then sawGb = true end
+end
+check(sawGb, "ROM scan still finds .gb when zip present")
+check(not sawZip, "ROM scan never lists .zip even beside .gb")
+
 -- Stub LauncherMods.installZip for rescan tests (NXMOD-02..04)
 local installCalls = {}
 local installBehavior = {} -- path -> {ok=bool, id=string|err}
@@ -232,10 +245,27 @@ eq(desk:_modsImportButtonLabel(), "Import mod .zip",
 check(desk:_modsDefaultHint():find("drop a mod", 1, true),
   "desktop default hint stays drop-oriented")
 
+-- Edge: id-already-exists conflict retains inbox zip (no silent delete)
+ri = freshImporter()
+installCalls = {}
+removed = {}
+love.filesystem.write("imports/mods/dup.zip", "DUP")
+installBehavior["imports/mods/dup.zip"] = {
+  ok = false, err = "mod id already installed",
+}
+ri:rescanModsAction()
+eq(#installCalls, 1, "conflict still attempts installZip")
+check(ri.modNotice and not ri.modNotice.ok, "conflict surfaces notice")
+check(not removed["imports/mods/dup.zip"], "conflict retains inbox zip")
+check(love.filesystem.read("imports/mods/dup.zip") == "DUP",
+  "conflict leaves zip bytes intact")
+
 -- Cleanup + restore stubs
 clearModsInbox()
 love.filesystem.remove("imports/other.zip")
 love.filesystem.remove("imports/modpack.zip")
+love.filesystem.remove("imports/cart.gb")
+love.filesystem.remove("imports/sidecar.zip")
 package.loaded["src.mods.LauncherMods"] = nil
 package.loaded["src.core.HostShell"] = nil
 love.system.getOS = saved.getOS