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/multiple-loaders/multiple-loaders.test.mjs

@@ -0,0 +1,6 @@
+import { register } from 'node:module'
+
+register('./typescript-loader.mjs', import.meta.url)
+register('../../hook.mjs', import.meta.url)
+
+await import('node:util')

node_modules/import-in-the-middle/test/multiple-loaders/typescript-loader.mjs

@@ -0,0 +1,26 @@
+/**
+ * This simulates what something like `tsx` (https://github.com/privatenumber/tsx)
+ * will do: it will try to resolve a URL with a `.js` extension to a `.ts` extension.
+ *
+ * Combined with the test case in the adjacent `multiple-loaders.test.mjs` file,
+ * this forces `import-in-the-middle` into what used to be a failure state: where
+ * `context.parentURL` is a `node:*` specifier and the `specifier` refers to a file
+ * that does not exist.
+ *
+ * See https://github.com/nodejs/node/issues/52987 for more details.
+ */
+export async function resolve (specifier, context, defaultResolve) {
+  if (!specifier.endsWith('.js') && !specifier.endsWith('.mjs')) {
+    return await defaultResolve(specifier, context)
+  }
+
+  try {
+    return await defaultResolve(specifier.replace(/\.m?js/, '.ts'), context)
+  } catch (err) {
+    if (err.code !== 'ERR_MODULE_NOT_FOUND') {
+      throw err
+    }
+
+    return await defaultResolve(specifier, context)
+  }
+}