Address review on the test harness

- The generic parts move to test/ in the repository root so other plugins can
  reuse them: the factorio and clusterio stubs, the test framework, the
  fengari runner, and clusterio's testMatrix and round trip helpers. A plugin
  composes them from its own env.lua, which adds its stubs and fixtures.
- Tests are declared with Test.test(name, fn) and every test function
  receives a fresh environment, so nothing carries over between them. A test
  which errors is reported as a failure rather than aborting the file.
- Every stub raises on properties it does not implement, which mirrors the
  game api. game.player is the one property allowed to read as nil.
- Test.deep_eq compares tables recursively with keys checked from both sides.
- The message records round trip through the same testMatrix and
  testRoundTripJsonSerialisable helpers the clusterio tests use, covering
  every optional field combination of the records, events and requests.
- controller.test.js and instance.test.js cover the node side of the plugin
  against faked controller and instance internals: property creation and
  sweeping, record building, broadcasts, subscription replay, assignment
  validation, auto assignment and its blocking role, seeding, the initialise
  payload, sync mode gating, and the rejection rollback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

exp_roles/test/module.test.js

@@ -1,8 +1,11 @@
 "use strict";
+const path = require("node:path");
 const t = require("tap");
-const { reportLuaTests } = require("./helpers/lua");
+const { reportLuaTests } = require("../../test/lua/runner");
 
-// Each file runs in its own lua state with a fresh copy of the module
+const envFile = path.join(__dirname, "lua", "env.lua");
+
+// Each file runs in its own lua state, and each test in a fresh environment
 for (const file of ["lookup.lua", "players.lua", "assignment.lua", "sync.lua", "holders.lua"]) {
-	t.test(file, subtest => reportLuaTests(subtest, file));
+	t.test(file, subtest => reportLuaTests(subtest, envFile, path.join(__dirname, "lua", file)));
 }