Fix stuff happening based on timers not being run correctly in unit tests (#5764)

* Introduce helper for advancing fake time

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

* Introduce reactive now to kludge around global shared state in library

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

* Replace all usages of "now" from mobx-utils with our own kludge to get rid of shared global state between unit tests

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

* Consolidate all usages of advanceTimersByTime to make sure things happening based on timers are run correctly

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

* Fix incorrect expect in test

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

* Enable skipped unit test since prerequisites are done

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

src/common/test-utils/use-fake-time.ts

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) OpenLens Authors. All rights reserved.
+ * Licensed under MIT License. See LICENSE in root directory for more information.
+ */
+import { act } from "@testing-library/react";
+
+let usingFakeTime = false;
+
+export const advanceFakeTime = (milliseconds: number) => {
+  if (!usingFakeTime) {
+    throw new Error("Tried to advance fake time but it was not enabled. Call useFakeTime() first.");
+  }
+
+  act(() => {
+    jest.advanceTimersByTime(milliseconds);
+  });
+};
+
+export const useFakeTime = (dateTime: string) => {
+  usingFakeTime = true;
+
+  jest.useFakeTimers();
+
+  jest.setSystemTime(new Date(dateTime));
+};