fix: Parse Server doesn't shutdown gracefully (#9634)

src/TestUtils.js

@@ -42,3 +42,42 @@ export function resolvingPromise() {
 export function sleep(ms) {
   return new Promise((resolve) => setTimeout(resolve, ms));
 }
+
+export function getConnectionsCount(server) {
+  return new Promise((resolve, reject) => {
+    server.getConnections((err, count) => {
+      /* istanbul ignore next */
+      if (err) {
+        reject(err);
+      } else {
+        resolve(count);
+      }
+    });
+  });
+};
+
+export class Connections {
+  constructor() {
+    this.sockets = new Set();
+  }
+
+  track(server) {
+    server.on('connection', socket => {
+      this.sockets.add(socket);
+      socket.on('close', () => {
+        this.sockets.delete(socket);
+      });
+    });
+  }
+
+  destroyAll() {
+    for (const socket of this.sockets.values()) {
+      socket.destroy();
+    }
+    this.sockets.clear();
+  }
+
+  count() {
+    return this.sockets.size;
+  }
+}