add test for getEtasForShuttleId cache

test/repositories/ApiBasedRepositoryTests.test.ts

@@ -206,12 +206,6 @@ describe("getEtaForShuttleAndStopId", () => {
     const repository = new ApiBasedRepository();
     const result = await repository.getEtaForShuttleAndStopId("5577", "177666");
 
-    const expectedEta: IEta = {
-      secondsRemaining: 587,
-      shuttleId: "5577",
-      stopId: "177666",
-    };
-
     expect(result?.secondsRemaining).toEqual(587);
     expect(result?.millisecondsSinceEpoch).toBeDefined();
   });
@@ -260,6 +254,8 @@ describe("getEtaForShuttleAndStopId", () => {
 
 describe("getEtasForShuttleId", () => {
   test("getEtasForShuttleId returns correct ETA data", async () => {
+    // Because I'm testing updateEtasForSystemIfTTL separately, force it to hit
+    // the cache for the stops
 
   });
 
@@ -268,7 +264,31 @@ describe("getEtasForShuttleId", () => {
   });
 
   test("getEtasForShuttleId returns old data if not expired", async () => {
+    updateGlobalFetchMockJson(genericEtaDataByStopId);
 
+    const initialCache: ApiBasedRepositoryCache = {
+      etasForStopId: {},
+      etasForShuttleId: {
+        "5577": [
+          {
+            secondsRemaining: 587,
+            shuttleId: "5577",
+            stopId: "177666",
+            millisecondsSinceEpoch: Date.now(),
+          }
+        ]
+      },
+    };
+
+    const ttls: ApiBasedRepositoryMillisecondTTLs = {
+      etasForShuttleId: 100000,
+      etasForStopId: 100000,
+    };
+
+    const repository = new ApiBasedRepository(initialCache, ttls);
+    const result = await repository.getEtasForShuttleId("5577");
+
+    expect(result).toEqual(initialCache.etasForShuttleId);
   });
 });