Add unit tests for role middleware

node_modules/jest-leak-detector/README.md

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+# jest-leak-detector
+
+Module for verifying whether an object has been garbage collected or not.
+
+Internally creates a weak reference to the object, and forces garbage collection to happen. If the reference is gone, it meant no one else was pointing to the object.
+
+## Example
+
+```javascript
+(async function () {
+  let reference = {};
+  let isLeaking;
+
+  const detector = new LeakDetector(reference, {
+    shouldGenerateV8HeapSnapshot: true,
+  });
+
+  // Reference is held in memory.
+  isLeaking = await detector.isLeaking();
+  console.log(isLeaking); // true
+
+  // We destroy the only reference to the object.
+  reference = null;
+
+  // Reference is gone.
+  isLeaking = await detector.isLeaking();
+  console.log(isLeaking); // false
+})();
+```