test: Mock bull, fix setInterval capturing memory in tests

Towards #3939

server/__mocks__/bull.ts

@@ -0,0 +1,43 @@
+export default class Queue {
+  done() {
+    //
+  }
+
+  on() {
+    //
+  }
+
+  count() {
+    return 0;
+  }
+
+  getDelayedCount() {
+    return 0;
+  }
+
+  add = function (data: any) {
+    const job = this.createJob(data);
+
+    if (!this.handler) {
+      throw Error(
+        "Mocking version requires handler to be set before first add()"
+      );
+    }
+
+    this.handler(job, this.done);
+  };
+
+  process = function (handler: any) {
+    if (this.handler) {
+      throw Error("Cannot define a handler more than once per Queue instance");
+    }
+
+    this.handler = handler;
+  };
+
+  createJob = function (data: any) {
+    return {
+      data: data,
+    };
+  };
+}

server/test/setup.ts

@@ -17,6 +17,8 @@ if (process.env.DATABASE_URL_TEST) {
 // so that sequelize uses the test config variables
 require("@server/database/sequelize");
 
+jest.mock("bull");
+
 // This is needed for the relative manual mock to be picked up
 jest.mock("../queues");
 

server/utils/queue.ts

@@ -41,9 +41,13 @@ export function createQueue(
   queue.on("failed", () => {
     Metrics.increment(`${prefix}.jobs.failed`);
   });
-  setInterval(async () => {
-    Metrics.gauge(`${prefix}.count`, await queue.count());
-    Metrics.gauge(`${prefix}.delayed_count`, await queue.getDelayedCount());
-  }, 5 * 1000);
+
+  if (env.ENVIRONMENT !== "test") {
+    setInterval(async () => {
+      Metrics.gauge(`${prefix}.count`, await queue.count());
+      Metrics.gauge(`${prefix}.delayed_count`, await queue.getDelayedCount());
+    }, 5 * 1000);
+  }
+
   return queue;
 }