update timed loader to use class composition

test/loaders/TimedApiBasedRepositoryLoaderTests.test.ts

@@ -0,0 +1,71 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it, jest } from "@jest/globals";
+import { TimedApiBasedRepositoryLoader } from "../../src/loaders/TimedApiBasedRepositoryLoader";
+import { resetGlobalFetchMockJson } from "../testHelpers/fetchMockHelpers";
+import { UnoptimizedInMemoryShuttleRepository } from "../../src/repositories/UnoptimizedInMemoryShuttleRepository";
+import { ApiBasedShuttleRepositoryLoader } from "../../src/loaders/ApiBasedShuttleRepositoryLoader";
+
+describe("TimedApiBasedRepositoryLoader", () => {
+  let timedLoader: TimedApiBasedRepositoryLoader;
+  let spies: any;
+
+  beforeAll(() => {
+    jest.useFakeTimers();
+    jest.spyOn(global, "setTimeout");
+  });
+
+  beforeEach(() => {
+    resetGlobalFetchMockJson();
+
+    const mockLoader = new ApiBasedShuttleRepositoryLoader(
+      "1",
+      "1",
+      new UnoptimizedInMemoryShuttleRepository(),
+    );
+    timedLoader = new TimedApiBasedRepositoryLoader(
+      mockLoader,
+    );
+
+    spies = {
+      fetchAndUpdateAll: jest.spyOn(mockLoader, 'fetchAndUpdateAll'),
+    };
+
+    Object.values(spies).forEach((spy: any) => {
+      spy.mockResolvedValue(undefined);
+    });
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+    jest.clearAllTimers();
+  })
+
+  describe("start", () => {
+    it("should update internal state, call data fetching methods, and start a timer", async () => {
+      await timedLoader.start();
+      expect(timedLoader["shouldBeRunning"]).toBe(true);
+
+      Object.values(spies).forEach((spy: any) => {
+        expect(spy).toHaveBeenCalled();
+      });
+
+      expect(setTimeout).toHaveBeenCalledWith(expect.any(Function), timedLoader.timeout);
+      expect(timedLoader.timeout).not.toBeUndefined();
+    });
+
+    it("does nothing if timer is already running", async () => {
+      await timedLoader.start();
+      await timedLoader.start();
+
+      Object.values(spies).forEach((spy: any) => {
+        expect(spy).toHaveBeenCalledTimes(1);
+      });
+    });
+  });
+
+  describe("stop", () => {
+    it("should update internal state", async () => {
+      timedLoader.stop();
+      expect(timedLoader['shouldBeRunning']).toBe(false);
+    });
+  });
+});