Update test framework: fix run_tests.py to support all test files, add auto-import-check for test files

node_modules/import-in-the-middle/test/hook/duplicate-exports.mjs

@@ -0,0 +1,19 @@
+import * as lib from '../fixtures/duplicate.mjs'
+import { notEqual, strictEqual } from 'assert'
+import Hook from '../../index.js'
+
+Hook((exports, name) => {
+  if (name.match(/duplicate\.mjs/)) {
+    // foo should not be exported because there are duplicate * exports
+    strictEqual('foo' in exports, false)
+    // default should be exported
+    strictEqual(exports.default, 'foo')
+  }
+})
+
+notEqual(lib, undefined)
+
+// foo should not be exported because there are duplicate exports
+strictEqual('foo' in lib, false)
+// default should be exported
+strictEqual(lib.default, 'foo')