diff --git a/test/loaders/TimedApiBasedRepositoryLoaderTests.test.ts b/test/loaders/TimedApiBasedRepositoryLoaderTests.test.ts
index 41d0011..236af2d 100644
--- a/test/loaders/TimedApiBasedRepositoryLoaderTests.test.ts
+++ b/test/loaders/TimedApiBasedRepositoryLoaderTests.test.ts
@@ -1,13 +1,70 @@
-import { beforeEach, describe } from "@jest/globals";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, jest } from "@jest/globals";
 import { TimedApiBasedRepositoryLoader } from "../../src/loaders/TimedApiBasedRepositoryLoader";
-import { UnoptimizedInMemoryRepository } from "../../src/repositories/UnoptimizedInMemoryRepository";
 import { resetGlobalFetchMockJson } from "../mockHelpers/fetchMockHelpers";
+import { GetterSetterRepository } from "../../src/repositories/GetterSetterRepository";
 
 describe("TimedApiBasedRepositoryLoader", () => {
+  let repositoryMock: GetterSetterRepository;
   let loader: TimedApiBasedRepositoryLoader;
+  let spies: any;
+
+  beforeAll(() => {
+    jest.useFakeTimers();
+    jest.spyOn(global, "setTimeout");
+  });
 
   beforeEach(() => {
-    loader = new TimedApiBasedRepositoryLoader(new UnoptimizedInMemoryRepository());
     resetGlobalFetchMockJson();
+
+    repositoryMock = {
+      clearSystemData: jest.fn(),
+      clearRouteData: jest.fn(),
+      clearStopData: jest.fn(),
+      clearShuttleData: jest.fn(),
+      clearEtaData: jest.fn(),
+    } as unknown as GetterSetterRepository;
+
+    loader = new TimedApiBasedRepositoryLoader(repositoryMock);
+
+    spies = {
+      fetchAndUpdateSystemData: jest.spyOn(loader, 'fetchAndUpdateSystemData'),
+      fetchAndUpdateRouteDataForExistingSystemsInRepository: jest.spyOn(loader, 'fetchAndUpdateRouteDataForExistingSystemsInRepository'),
+      fetchAndUpdateStopAndPolylineDataForRoutesInExistingSystemsInRepository: jest.spyOn(loader, 'fetchAndUpdateStopAndPolylineDataForRoutesInExistingSystemsInRepository'),
+      fetchAndUpdateShuttleDataForExistingSystemsInRepository: jest.spyOn(loader, 'fetchAndUpdateShuttleDataForExistingSystemsInRepository'),
+      fetchAndUpdateEtaDataForExistingStopsForSystemsInRepository: jest.spyOn(loader, 'fetchAndUpdateEtaDataForExistingStopsForSystemsInRepository')
+    };
+
+    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 loader.start();
+      expect(loader["shouldBeRunning"]).toBe(true);
+
+      Object.values(repositoryMock).forEach((mockFn) => {
+        expect(mockFn).toHaveBeenCalled();
+      });
+      Object.values(spies).forEach((spy: any) => {
+        expect(spy).toHaveBeenCalled();
+      });
+
+      expect(setTimeout).toHaveBeenCalledWith(expect.any(Function), loader.timeout);
+      expect(loader.timeout).not.toBeUndefined();
+    });
+  });
+
+  describe("stop", () => {
+    it("should update internal state", async () => {
+      loader.stop();
+      expect(loader['shouldBeRunning']).toBe(false);
+    });
   });
 });
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