diff --git a/test/generators.ts b/test/generators.ts
index 6efcef7..eac524a 100644
--- a/test/generators.ts
+++ b/test/generators.ts
@@ -1,4 +1,4 @@
-import { IOrderedStop, IRoute, IShuttle, IStop, ISystem } from "../src/entities/entities";
+import { IEta, IOrderedStop, IRoute, IShuttle, IStop, ISystem } from "../src/entities/entities";
 
 // Use a single set of generators in case any of the
 // interfaces change in the future
@@ -42,4 +42,12 @@ export function generateMockOrderedStops(): IOrderedStop[] {
     { stopId: "st2", routeId: "r1", position: 3 },
     { stopId: "st2", routeId: "r2", position: 4 },
   ];
+}
+
+export function generateMockEtas(): IEta[] {
+  return [
+    { shuttleId: "sh1", stopId: "st1", secondsRemaining: 120 },
+    { shuttleId: "sh1", stopId: "st2", secondsRemaining: 180 },
+    { shuttleId: "sh2", stopId: "st3", secondsRemaining: 240 },
+  ];
 }
\ No newline at end of file
diff --git a/test/repositories/UnoptimizedInMemoryRepositoryTests.test.ts b/test/repositories/UnoptimizedInMemoryRepositoryTests.test.ts
index 58e1e7d..e9e8166 100644
--- a/test/repositories/UnoptimizedInMemoryRepositoryTests.test.ts
+++ b/test/repositories/UnoptimizedInMemoryRepositoryTests.test.ts
@@ -1,6 +1,7 @@
 import { beforeEach, describe, expect, test } from "@jest/globals";
 import { UnoptimizedInMemoryRepository } from "../../src/repositories/UnoptimizedInMemoryRepository";
 import {
+  generateMockEtas,
   generateMockOrderedStops,
   generateMockRoutes,
   generateMockShuttles,
@@ -176,11 +177,7 @@ describe("UnoptimizedInMemoryRepository", () => {
 
   describe("getEtasForShuttleId", () => {
     test("gets ETAs for a specific shuttle ID", async () => {
-      const mockEtas = [
-        { shuttleId: "sh1", stopId: "st1", secondsRemaining: 120 },
-        { shuttleId: "sh1", stopId: "st2", secondsRemaining: 180 },
-        { shuttleId: "sh2", stopId: "st3", secondsRemaining: 240 },
-      ];
+      const mockEtas = generateMockEtas();
       for (const eta of mockEtas) {
         await repository.addOrUpdateEta(eta);
       }
@@ -197,11 +194,7 @@ describe("UnoptimizedInMemoryRepository", () => {
 
   describe("getEtasForStopId", () => {
     test("gets ETAs for a specific stop ID", async () => {
-      const mockEtas = [
-        { shuttleId: "s1", stopId: "st1", secondsRemaining: 120 },
-        { shuttleId: "s2", stopId: "st1", secondsRemaining: 180 },
-        { shuttleId: "s3", stopId: "st2", secondsRemaining: 240 },
-      ];
+      const mockEtas = generateMockEtas();
       for (const eta of mockEtas) {
         await repository.addOrUpdateEta(eta);
       }
@@ -218,7 +211,8 @@ describe("UnoptimizedInMemoryRepository", () => {
 
   describe("getEtaForShuttleAndStopId", () => {
     test("gets a single ETA for a specific shuttle and stop ID", async () => {
-      const mockEta = { shuttleId: "sh1", stopId: "st1", secondsRemaining: 120 };
+      const mockEtas = generateMockEtas();
+      const mockEta = mockEtas[0];
       await repository.addOrUpdateEta(mockEta);
 
       const result = await repository.getEtaForShuttleAndStopId("sh1", "st1");
@@ -412,22 +406,25 @@ describe("UnoptimizedInMemoryRepository", () => {
 
   describe("addOrUpdateEta", () => {
     test("adds a new ETA if nonexistent", async () => {
-      const newEta = { shuttleId: "shuttle1", stopId: "stop1", secondsRemaining: 120 };
+      const mockEtas = generateMockEtas();
+      const newEta = mockEtas[0];
 
       await repository.addOrUpdateEta(newEta);
 
-      const result = await repository.getEtasForShuttleId("shuttle1");
+      const result = await repository.getEtasForShuttleId(newEta.shuttleId);
       expect(result).toEqual([newEta]);
     });
 
     test("updates an existing ETA if it exists", async () => {
-      const existingEta = { shuttleId: "shuttle1", stopId: "stop1", secondsRemaining: 120 };
-      const updatedEta = { shuttleId: "shuttle1", stopId: "stop1", secondsRemaining: 60 };
+      const mockEtas = generateMockEtas();
+      const existingEta = mockEtas[0];
+      const updatedEta = structuredClone(existingEta);
+      updatedEta.secondsRemaining = existingEta.secondsRemaining + 60;
 
       await repository.addOrUpdateEta(existingEta);
       await repository.addOrUpdateEta(updatedEta);
 
-      const result = await repository.getEtasForShuttleId("shuttle1");
+      const result = await repository.getEtasForShuttleId(existingEta.shuttleId);
       expect(result).toEqual([updatedEta]);
     });
   });
@@ -473,11 +470,10 @@ describe("UnoptimizedInMemoryRepository", () => {
 
   describe("clearEtaData", () => {
     test("clears all ETAs from the repository", async () => {
-      const eta1 = { shuttleId: "shuttle1", stopId: "stop1", secondsRemaining: 120 };
-      const eta2 = { shuttleId: "shuttle2", stopId: "stop2", secondsRemaining: 150 };
-
-      await repository.addOrUpdateEta(eta1);
-      await repository.addOrUpdateEta(eta2);
+      const mockEtas = generateMockEtas();
+      for (const eta of mockEtas) {
+        await repository.addOrUpdateEta(eta);
+      }
 
       await repository.clearEtaData();