Cover required imports across platforms

tests/engine/uwp_native_picker_test.lua

@@ -44,6 +44,46 @@ check(importer.installedPath == [[C:\LocalState\picked_mod.zip]],
 check(removedPath == [[C:\LocalState\picked_mod.zip]],
   "removes the temporary copy after installation")
 
+-- The UWP picker returns a temporary path rather than a mobile staged name.
+-- Required imports must use that same picker and remain scoped to the selected
+-- mod instead of relying on a desktop shell or Android/iOS inbox handling.
+local pickedKind
+love.system.pickFile = function(kind)
+  pickedKind = kind
+  return true
+end
+love.system.getPickedFile = function()
+  love.system.getPickedFile = function() return nil end
+  return [[C:\LocalState\picked_required_import.bin]]
+end
+removedPath = nil
+local required = RomImporter.new(function() end, { launcher = true })
+required.mods = { {
+  id = "needs-source",
+  manifest = {
+    id = "needs-source", name = "Needs source",
+    required_imports = { {
+      id = "source", name = "Source", file = "source.bin",
+      md5 = { "00000000000000000000000000000000" },
+    } },
+  },
+} }
+required._importRequiredSource = function(self, modId, importId, path)
+  self.requiredPath = { modId = modId, importId = importId, path = path }
+  return true
+end
+required:chooseRequiredImport("needs-source", "source")
+check(pickedKind == "required_import", "UWP requests the required-import picker kind")
+required:update(0)
+check(required.requiredPath and required.requiredPath.path
+    == [[C:\LocalState\picked_required_import.bin]],
+  "UWP routes the picked dependency to its declared import")
+check(required.requiredPath.modId == "needs-source"
+    and required.requiredPath.importId == "source",
+  "UWP preserves the pending mod and import identity")
+check(removedPath == [[C:\LocalState\picked_required_import.bin]],
+  "UWP removes its temporary required-import copy after validation")
+
 love.system.getOS = saved.getOS
 love.system.pickFile = saved.pickFile
 love.system.getPickedFile = saved.getPickedFile