add testing logic for scheduleNotification test

test/services/NotificationServiceTests.test.ts

@@ -2,6 +2,7 @@ import { beforeEach, describe, expect, it, jest } from "@jest/globals";
 import { NotificationService } from "../../src/services/NotificationService";
 import { UnoptimizedInMemoryRepository } from "../../src/repositories/UnoptimizedInMemoryRepository";
 import fs from "fs";
+import { IEta } from "../../src/entities/entities";
 
 jest.mock("fs");
 
@@ -49,7 +50,23 @@ describe("NotificationService", () => {
 
   describe("scheduleNotification", () => {
     it("sends a notification to given shuttle/stop ID when changed", async () => {
+      // Arrange
+      const eta: IEta = {
+        shuttleId: "1",
+        stopId: "1",
+        secondsRemaining: 120,
+      };
 
+      // Act
+      await notificationService.scheduleNotification({
+        deviceId: "1",
+        shuttleId: eta.shuttleId,
+        stopId: eta.stopId,
+      });
+      await repository.addOrUpdateEta(eta);
+
+      // Assert
+      // ...that notification (fetch request) was sent
     });
 
     it("clears the notification after delivering successfully", async () => {