add json snapshot and test cases for method

test/jsonSnapshots/fetchStopAndPolylineData/fetchStopAndPolylineDataSuccessfulResponse.ts

@@ -1,4 +1,4 @@
-export const fetchStopAndPolylineDataForRoutesWithSystemId = {
+export const fetchStopAndPolylineDataSuccessfulResponse = {
   "stops": {
     "ID2032": {
       "routeId": "54529",

test/loaders/ApiBasedRepositoryLoaderTests.test.ts

@@ -5,6 +5,9 @@ import { fetchSystemDataSuccessfulResponse } from "../jsonSnapshots/fetchSystemD
 import { fetchSystemDataFailedResponse } from "../jsonSnapshots/fetchSystemData/fetchSystemDataFailedResponse";
 import { fetchRouteDataSuccessfulResponse } from "../jsonSnapshots/fetchRouteData/fetchRouteDataSuccessfulResponse";
 import { ISystem } from "../../src/entities/entities";
+import {
+  fetchStopAndPolylineDataSuccessfulResponse
+} from "../jsonSnapshots/fetchStopAndPolylineData/fetchStopAndPolylineDataSuccessfulResponse";
 
 /**
  * Function to update behavior of the global `fetch` function.
@@ -134,13 +137,41 @@ describe("ApiBasedRepositoryLoader", () => {
     });
   });
 
-  describe("fetchAndUpdateStopAndPolylineDataForRoutesInExistingSystems", () => {
+  describe("fetchAndUpdateStopAndPolylineDataForRoutesWithSystemId", () => {
     it("updates stop and polyline data if there are systems and response received", async () => {
+      updateGlobalFetchMockJson(fetchStopAndPolylineDataSuccessfulResponse);
 
+      const stopsArray = Object.values(fetchStopAndPolylineDataSuccessfulResponse.stops);
+
+      await loader.fetchAndUpdateStopAndPolylineDataForRoutesWithSystemId("263");
+
+      const stops = await loader.repository.getStopsBySystemId("263");
+      expect(stops.length).toEqual(stopsArray.length);
+
+      await Promise.all(stops.map(async (stop) => {
+        const orderedStops = await loader.repository.getOrderedStopsByStopId(stop.id)
+        expect(orderedStops.length).toBeGreaterThan(0);
+      }));
+
+      const routes = await loader.repository.getRoutesBySystemId("263");
+      routes.forEach((route) => {
+        expect(route.polylineCoordinates.length).toBeGreaterThan(0);
+      });
     });
 
     it("throws the correct error if the API response contains no data", async () => {
+      // @ts-ignore
+      global.fetch = jest.fn(() => {
+        return Promise.resolve({
+          json: () => Promise.reject(new SyntaxError("Unable to parse JSON")),
+          status: 200,
+          ok: true,
+        })
+      }) as jest.Mock;
 
+      await assertAsyncCallbackThrowsApiResponseError(async () => {
+        await loader.fetchAndUpdateStopAndPolylineDataForRoutesWithSystemId("263");
+      });
     })
   });