[ESM] Convert *most* of test-folder to use standard modules

test/testutils.mjs

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2014 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fs from "fs";
+import path from "path";
+import rimraf from "rimraf";
+
+const rimrafSync = rimraf.sync;
+
+function removeDirSync(dir) {
+  fs.readdirSync(dir); // Will throw if dir is not a directory
+  rimrafSync(dir, {
+    disableGlob: true,
+  });
+}
+
+function copySubtreeSync(src, dest) {
+  const files = fs.readdirSync(src);
+  if (!fs.existsSync(dest)) {
+    fs.mkdirSync(dest);
+  }
+  files.forEach(function (filename) {
+    const srcFile = path.join(src, filename);
+    const file = path.join(dest, filename);
+    const stats = fs.statSync(srcFile);
+    if (stats.isDirectory()) {
+      copySubtreeSync(srcFile, file);
+    } else {
+      fs.writeFileSync(file, fs.readFileSync(srcFile));
+    }
+  });
+}
+
+function ensureDirSync(dir) {
+  if (fs.existsSync(dir)) {
+    return;
+  }
+  const parts = dir.split(path.sep);
+  let i = parts.length;
+  while (i > 1 && !fs.existsSync(parts.slice(0, i - 1).join(path.sep))) {
+    i--;
+  }
+  if (i < 0 || (i === 0 && parts[0])) {
+    throw new Error();
+  }
+
+  while (i <= parts.length) {
+    fs.mkdirSync(parts.slice(0, i).join(path.sep));
+    i++;
+  }
+}
+
+export { copySubtreeSync, ensureDirSync, removeDirSync };