diff --git a/frontend/app/component/form/data_entry/PollingStationFormController.test.tsx b/frontend/app/component/form/data_entry/PollingStationFormController.test.tsx
index 3b5336eeb..85b0971b4 100644
--- a/frontend/app/component/form/data_entry/PollingStationFormController.test.tsx
+++ b/frontend/app/component/form/data_entry/PollingStationFormController.test.tsx
@@ -1,14 +1,18 @@
 import * as React from "react";
 
-import { describe, expect, test } from "vitest";
+import { beforeEach, describe, expect, test } from "vitest";
 
 import { PollingStationFormController } from "app/component/form/data_entry/PollingStationFormController";
 import { usePollingStationFormController } from "app/component/form/data_entry/usePollingStationFormController";
 import { errorWarningMocks } from "app/component/form/testHelperFunctions";
 
 import { SaveDataEntryResponse } from "@kiesraad/api";
-import { electionMockData } from "@kiesraad/api-mocks";
-import { overrideOnce, Providers, renderHook, waitFor } from "@kiesraad/test";
+import {
+  electionMockData,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { overrideOnce, Providers, renderHook, server, waitFor } from "@kiesraad/test";
 
 const Wrapper = ({ children }: { children: React.ReactNode }) => (
   <Providers>
@@ -19,6 +23,9 @@ const Wrapper = ({ children }: { children: React.ReactNode }) => (
 );
 
 describe("PollingStationFormController", () => {
+  beforeEach(() => {
+    server.use(PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
   test("PollingStationFormController renderHook", async () => {
     const { result } = renderHook(() => usePollingStationFormController(), {
       wrapper: Wrapper,
diff --git a/frontend/app/component/form/data_entry/candidates_votes/CandidatesVotesForm.test.tsx b/frontend/app/component/form/data_entry/candidates_votes/CandidatesVotesForm.test.tsx
index a159f85a2..bffcf81e4 100644
--- a/frontend/app/component/form/data_entry/candidates_votes/CandidatesVotesForm.test.tsx
+++ b/frontend/app/component/form/data_entry/candidates_votes/CandidatesVotesForm.test.tsx
@@ -1,5 +1,5 @@
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import {
   Election,
@@ -7,8 +7,13 @@ import {
   POLLING_STATION_DATA_ENTRY_SAVE_REQUEST_BODY,
   PollingStationResults,
 } from "@kiesraad/api";
-import { electionMockData, politicalGroupMockData } from "@kiesraad/api-mocks";
-import { getUrlMethodAndBody, overrideOnce, render, screen, within } from "@kiesraad/test";
+import {
+  electionMockData,
+  politicalGroupMockData,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { getUrlMethodAndBody, overrideOnce, render, screen, server, within } from "@kiesraad/test";
 
 import {
   emptyDataEntryRequest,
@@ -41,6 +46,10 @@ const candidatesFieldIds = {
 };
 
 describe("Test CandidatesVotesForm", () => {
+  beforeEach(() => {
+    server.use(PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
+
   describe("CandidatesVotesForm renders correctly", () => {
     test("Candidates with first name", async () => {
       const politicalGroupMockData: PoliticalGroup = {
diff --git a/frontend/app/component/form/data_entry/check_and_save/CheckAndSaveForm.test.tsx b/frontend/app/component/form/data_entry/check_and_save/CheckAndSaveForm.test.tsx
index c607f424e..54942a97a 100644
--- a/frontend/app/component/form/data_entry/check_and_save/CheckAndSaveForm.test.tsx
+++ b/frontend/app/component/form/data_entry/check_and_save/CheckAndSaveForm.test.tsx
@@ -2,7 +2,12 @@ import { userEvent } from "@testing-library/user-event";
 import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { ElectionProvider, PollingStationResults } from "@kiesraad/api";
-import { electionDetailsMockResponse, electionMockData } from "@kiesraad/api-mocks";
+import {
+  electionMockData,
+  ElectionRequestHandler,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
 import { overrideOnce, renderReturningRouter, screen, server, within } from "@kiesraad/test";
 
 import { defaultFormState, emptyDataEntryRequest, errorWarningMocks } from "../../testHelperFunctions";
@@ -29,7 +34,7 @@ function renderForm(defaultFormState: Partial<FormState> = {}, defaultValues?: P
 
 describe("Test CheckAndSaveForm", () => {
   beforeEach(() => {
-    overrideOnce("get", "/api/elections/1", 200, electionDetailsMockResponse);
+    server.use(ElectionRequestHandler, PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
   });
 
   test("Data entry can be finalised", async () => {
@@ -130,6 +135,9 @@ describe("Test CheckAndSaveForm", () => {
 });
 
 describe("Test CheckAndSaveForm summary", () => {
+  beforeEach(() => {
+    server.use(ElectionRequestHandler, PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
   test("Blocking", async () => {
     const formState = structuredClone(defaultFormState);
     formState.sections.voters_votes_counts.errors = [errorWarningMocks.F201];
diff --git a/frontend/app/component/form/data_entry/differences/DifferencesForm.test.tsx b/frontend/app/component/form/data_entry/differences/DifferencesForm.test.tsx
index d5aedc7ed..a709b7253 100644
--- a/frontend/app/component/form/data_entry/differences/DifferencesForm.test.tsx
+++ b/frontend/app/component/form/data_entry/differences/DifferencesForm.test.tsx
@@ -1,5 +1,5 @@
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import {
   emptyDataEntryRequest,
@@ -10,8 +10,12 @@ import {
 } from "app/component/form/testHelperFunctions";
 
 import { POLLING_STATION_DATA_ENTRY_SAVE_REQUEST_BODY, PollingStationResults } from "@kiesraad/api";
-import { electionMockData } from "@kiesraad/api-mocks";
-import { getUrlMethodAndBody, overrideOnce, render, screen, userTypeInputs } from "@kiesraad/test";
+import {
+  electionMockData,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { getUrlMethodAndBody, overrideOnce, render, screen, server, userTypeInputs } from "@kiesraad/test";
 
 import { PollingStationFormController } from "../PollingStationFormController";
 import { DifferencesForm } from "./DifferencesForm";
@@ -40,6 +44,10 @@ const differencesFieldIds = {
 };
 
 describe("Test DifferencesForm", () => {
+  beforeEach(() => {
+    server.use(PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
+
   describe("DifferencesForm user interactions", () => {
     test("hitting enter key does not result in api call", async () => {
       const user = userEvent.setup();
diff --git a/frontend/app/component/form/data_entry/polling_station_choice/PollingStationChoiceForm.test.tsx b/frontend/app/component/form/data_entry/polling_station_choice/PollingStationChoiceForm.test.tsx
index 7080170ea..5e4678123 100644
--- a/frontend/app/component/form/data_entry/polling_station_choice/PollingStationChoiceForm.test.tsx
+++ b/frontend/app/component/form/data_entry/polling_station_choice/PollingStationChoiceForm.test.tsx
@@ -1,12 +1,17 @@
 import { waitFor } from "@testing-library/react";
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test } from "vitest";
+import { beforeEach, describe, expect, test } from "vitest";
 
 import { PollingStationChoiceForm } from "app/component/form/data_entry/polling_station_choice/PollingStationChoiceForm";
 
 import { ElectionProvider, ElectionStatusProvider, ElectionStatusResponse } from "@kiesraad/api";
-import { electionDetailsMockResponse, electionStatusMockResponse } from "@kiesraad/api-mocks";
-import { overrideOnce, render, renderReturningRouter, screen, within } from "@kiesraad/test";
+import {
+  electionDetailsMockResponse,
+  ElectionRequestHandler,
+  electionStatusMockResponse,
+  ElectionStatusRequestHandler,
+} from "@kiesraad/api-mocks";
+import { overrideOnce, render, renderReturningRouter, screen, server, within } from "@kiesraad/test";
 
 function renderPollingStationChoicePage() {
   return renderReturningRouter(
@@ -19,6 +24,9 @@ function renderPollingStationChoicePage() {
 }
 
 describe("Test PollingStationChoiceForm", () => {
+  beforeEach(() => {
+    server.use(ElectionStatusRequestHandler);
+  });
   describe("Polling station choice form", () => {
     test("Form field entry", async () => {
       overrideOnce("get", "/api/elections/1", 200, electionDetailsMockResponse);
@@ -305,6 +313,7 @@ describe("Test PollingStationChoiceForm", () => {
 
   describe("Polling station in progress", () => {
     test("Show polling stations as 'in progress'", async () => {
+      server.use(ElectionRequestHandler);
       overrideOnce("get", "api/elections/1/status", 200, {
         statuses: [
           { polling_station_id: 1, status: "first_entry_not_started" },
diff --git a/frontend/app/component/form/data_entry/recounted/RecountedForm.test.tsx b/frontend/app/component/form/data_entry/recounted/RecountedForm.test.tsx
index eb7e0ad73..a9dd91a56 100644
--- a/frontend/app/component/form/data_entry/recounted/RecountedForm.test.tsx
+++ b/frontend/app/component/form/data_entry/recounted/RecountedForm.test.tsx
@@ -1,11 +1,15 @@
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { emptyDataEntryRequest, errorWarningMocks } from "app/component/form/testHelperFunctions";
 
 import { POLLING_STATION_DATA_ENTRY_SAVE_REQUEST_BODY, SaveDataEntryResponse } from "@kiesraad/api";
-import { electionMockData } from "@kiesraad/api-mocks";
-import { getUrlMethodAndBody, overrideOnce, render, screen } from "@kiesraad/test";
+import {
+  electionMockData,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { getUrlMethodAndBody, overrideOnce, render, screen, server } from "@kiesraad/test";
 
 import { PollingStationFormController } from "../PollingStationFormController";
 import { RecountedForm } from "./RecountedForm";
@@ -17,6 +21,9 @@ const Component = (
 );
 
 describe("Test RecountedForm", () => {
+  beforeEach(() => {
+    server.use(PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
   describe("RecountedForm user interactions", () => {
     test("hitting enter key does not result in api call", async () => {
       render(Component);
diff --git a/frontend/app/component/form/data_entry/voters_and_votes/VotersAndVotesForm.test.tsx b/frontend/app/component/form/data_entry/voters_and_votes/VotersAndVotesForm.test.tsx
index d1411dbcf..cd89fc80d 100644
--- a/frontend/app/component/form/data_entry/voters_and_votes/VotersAndVotesForm.test.tsx
+++ b/frontend/app/component/form/data_entry/voters_and_votes/VotersAndVotesForm.test.tsx
@@ -1,5 +1,5 @@
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import {
   emptyDataEntryRequest,
@@ -10,8 +10,12 @@ import {
 } from "app/component/form/testHelperFunctions";
 
 import { POLLING_STATION_DATA_ENTRY_SAVE_REQUEST_BODY, PollingStationResults } from "@kiesraad/api";
-import { electionMockData } from "@kiesraad/api-mocks";
-import { getUrlMethodAndBody, overrideOnce, render, screen, userTypeInputs, waitFor } from "@kiesraad/test";
+import {
+  electionMockData,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { getUrlMethodAndBody, overrideOnce, render, screen, server, userTypeInputs, waitFor } from "@kiesraad/test";
 
 import { FormState, PollingStationFormController } from "../PollingStationFormController";
 import { VotersAndVotesForm } from "./VotersAndVotesForm";
@@ -91,6 +95,10 @@ const recountFieldIds = {
 };
 
 describe("Test VotersAndVotesForm", () => {
+  beforeEach(() => {
+    server.use(PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
+  });
+
   describe("VotersAndVotesForm user interactions", () => {
     test("hitting enter key does not result in api call", async () => {
       const user = userEvent.setup();
@@ -124,10 +132,6 @@ describe("Test VotersAndVotesForm", () => {
     });
 
     test("Form field entry and keybindings", async () => {
-      overrideOnce("post", "/api/polling_stations/1/data_entries/1", 200, {
-        validation_results: { errors: [], warnings: [] },
-      });
-
       const user = userEvent.setup();
 
       renderForm({ recounted: true });
diff --git a/frontend/app/component/form/polling_station/PollingStationForm.test.tsx b/frontend/app/component/form/polling_station/PollingStationForm.test.tsx
index 0633a00f8..f3f2532e2 100644
--- a/frontend/app/component/form/polling_station/PollingStationForm.test.tsx
+++ b/frontend/app/component/form/polling_station/PollingStationForm.test.tsx
@@ -1,8 +1,9 @@
 import { UserEvent, userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { ErrorResponse, PollingStation } from "@kiesraad/api";
-import { overrideOnce, render, screen, waitFor } from "@kiesraad/test";
+import { PollingStationCreateHandler, PollingStationUpdateHandler } from "@kiesraad/api-mocks";
+import { overrideOnce, render, screen, server, waitFor } from "@kiesraad/test";
 
 import { PollingStationForm } from "./PollingStationForm";
 
@@ -43,6 +44,9 @@ async function fillForm(user: UserEvent, testPollingStation: PollingStation | Om
 }
 
 describe("PollingStationForm", () => {
+  beforeEach(() => {
+    server.use(PollingStationCreateHandler, PollingStationUpdateHandler);
+  });
   describe("PollingStationForm create", () => {
     test("Successful create", async () => {
       const testPollingStation: Omit<PollingStation, "id"> = {
diff --git a/frontend/app/module/data_entry/page/DataEntryHomePage.test.tsx b/frontend/app/module/data_entry/page/DataEntryHomePage.test.tsx
index cb3b4df62..d8f0c12e3 100644
--- a/frontend/app/module/data_entry/page/DataEntryHomePage.test.tsx
+++ b/frontend/app/module/data_entry/page/DataEntryHomePage.test.tsx
@@ -6,8 +6,13 @@ import { beforeEach, describe, expect, test } from "vitest";
 import { routes } from "app/routes";
 
 import { ElectionProvider, ElectionStatusProvider, ElectionStatusResponse } from "@kiesraad/api";
-import { electionDetailsMockResponse } from "@kiesraad/api-mocks";
-import { overrideOnce, Providers, render, screen, setupTestRouter, waitFor, within } from "@kiesraad/test";
+import {
+  electionDetailsMockResponse,
+  ElectionListRequestHandler,
+  ElectionRequestHandler,
+  ElectionStatusRequestHandler,
+} from "@kiesraad/api-mocks";
+import { overrideOnce, Providers, render, screen, server, setupTestRouter, waitFor, within } from "@kiesraad/test";
 
 import { DataEntryHomePage } from "./DataEntryHomePage";
 
@@ -22,6 +27,7 @@ const renderDataEntryHomePage = () =>
 
 describe("DataEntryHomePage", () => {
   beforeEach(() => {
+    server.use(ElectionListRequestHandler, ElectionRequestHandler, ElectionStatusRequestHandler);
     overrideOnce("get", "/api/elections/1", 200, electionDetailsMockResponse);
   });
 
diff --git a/frontend/app/module/data_entry/polling_station/AbortDataEntryControl.test.tsx b/frontend/app/module/data_entry/polling_station/AbortDataEntryControl.test.tsx
index eda6932ac..ec5edf111 100644
--- a/frontend/app/module/data_entry/polling_station/AbortDataEntryControl.test.tsx
+++ b/frontend/app/module/data_entry/polling_station/AbortDataEntryControl.test.tsx
@@ -8,8 +8,14 @@ import {
   POLLING_STATION_DATA_ENTRY_SAVE_REQUEST_BODY,
   SaveDataEntryResponse,
 } from "@kiesraad/api";
-import { electionDetailsMockResponse, electionMockData } from "@kiesraad/api-mocks";
-import { overrideOnce, renderReturningRouter, screen, server } from "@kiesraad/test";
+import {
+  electionMockData,
+  ElectionRequestHandler,
+  PollingStationDataEntryDeleteHandler,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
+import { renderReturningRouter, screen, server } from "@kiesraad/test";
 
 import { PollingStationFormController } from "../../../component/form/data_entry/PollingStationFormController";
 import { VotersAndVotesForm } from "../../../component/form/data_entry/voters_and_votes/VotersAndVotesForm";
@@ -29,7 +35,7 @@ const renderAbortDataEntryControl = () => {
 
 describe("Test AbortDataEntryControl", () => {
   beforeEach(() => {
-    overrideOnce("get", "/api/elections/1", 200, electionDetailsMockResponse);
+    server.use(ElectionRequestHandler, PollingStationDataEntryGetHandler, PollingStationDataEntrySaveHandler);
   });
 
   test("renders and toggles the modal", async () => {
@@ -98,7 +104,7 @@ describe("Test AbortDataEntryControl", () => {
 
     // set up a listener to check if the delete request is made
     let request_method, request_url;
-    overrideOnce("delete", "/api/polling_stations/1/data_entries/1", 204, null);
+    server.use(PollingStationDataEntryDeleteHandler);
     server.events.on("request:start", ({ request }) => {
       request_method = request.method;
       request_url = request.url;
diff --git a/frontend/app/module/data_entry/polling_station/PollingStation.test.tsx b/frontend/app/module/data_entry/polling_station/PollingStation.test.tsx
index 97d77d988..436a591d6 100644
--- a/frontend/app/module/data_entry/polling_station/PollingStation.test.tsx
+++ b/frontend/app/module/data_entry/polling_station/PollingStation.test.tsx
@@ -1,17 +1,26 @@
 import { render as rtlRender } from "@testing-library/react";
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { errorWarningMocks } from "app/component/form/testHelperFunctions";
 import { routes } from "app/routes";
 
 import { SaveDataEntryResponse } from "@kiesraad/api";
-import { electionMockData } from "@kiesraad/api-mocks";
+import {
+  ElectionListRequestHandler,
+  electionMockData,
+  ElectionRequestHandler,
+  ElectionStatusRequestHandler,
+  PollingStationDataEntryDeleteHandler,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+} from "@kiesraad/api-mocks";
 import {
   overrideOnce,
   Providers,
   Router,
   screen,
+  server,
   setupTestRouter,
   userTypeInputs,
   waitFor,
@@ -298,6 +307,16 @@ async function executeStepsForPendingChanges(router: Router) {
 }
 
 describe("Polling Station data entry integration tests", () => {
+  beforeEach(() => {
+    server.use(
+      ElectionListRequestHandler,
+      ElectionRequestHandler,
+      ElectionStatusRequestHandler,
+      PollingStationDataEntryGetHandler,
+      PollingStationDataEntrySaveHandler,
+      PollingStationDataEntryDeleteHandler,
+    );
+  });
   describe("Navigation through the form", () => {
     test("Fill in complete form", async () => {
       const router = renderWithRouter();
diff --git a/frontend/app/module/data_entry/polling_station/PollingStationLayout.test.tsx b/frontend/app/module/data_entry/polling_station/PollingStationLayout.test.tsx
index 10bb5b58f..9f7b34b40 100644
--- a/frontend/app/module/data_entry/polling_station/PollingStationLayout.test.tsx
+++ b/frontend/app/module/data_entry/polling_station/PollingStationLayout.test.tsx
@@ -3,8 +3,16 @@ import { beforeEach, describe, expect, test, vi } from "vitest";
 import { PollingStationLayout } from "app/module/data_entry";
 
 import { Election, ElectionListProvider, ElectionProvider, ElectionStatusProvider } from "@kiesraad/api";
-import { electionDetailsMockResponse, pollingStationMockData } from "@kiesraad/api-mocks";
-import { overrideOnce, render, screen, within } from "@kiesraad/test";
+import {
+  electionDetailsMockResponse,
+  ElectionListRequestHandler,
+  ElectionRequestHandler,
+  ElectionStatusRequestHandler,
+  PollingStationDataEntryGetHandler,
+  PollingStationDataEntrySaveHandler,
+  pollingStationMockData,
+} from "@kiesraad/api-mocks";
+import { render, screen, server, within } from "@kiesraad/test";
 
 import { PollingStationFormController } from "../../../component/form/data_entry/PollingStationFormController";
 
@@ -17,7 +25,13 @@ describe("PollingStationLayout", () => {
   const election = electionDetailsMockResponse.election as Required<Election>;
 
   beforeEach(() => {
-    overrideOnce("get", "/api/elections/1", 200, electionDetailsMockResponse);
+    server.use(
+      ElectionListRequestHandler,
+      ElectionRequestHandler,
+      ElectionStatusRequestHandler,
+      PollingStationDataEntryGetHandler,
+      PollingStationDataEntrySaveHandler,
+    );
   });
 
   test("Render", async () => {
diff --git a/frontend/app/module/election/page/ElectionReportPage.test.tsx b/frontend/app/module/election/page/ElectionReportPage.test.tsx
index 7cc8faa29..87bd0f539 100644
--- a/frontend/app/module/election/page/ElectionReportPage.test.tsx
+++ b/frontend/app/module/election/page/ElectionReportPage.test.tsx
@@ -1,13 +1,18 @@
 import { render as rtlRender } from "@testing-library/react";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { ElectionReportPage } from "app/module/election";
 import { routes } from "app/routes";
 
 import { ElectionProvider, ElectionStatusProvider } from "@kiesraad/api";
-import { expectErrorPage, overrideOnce, Providers, render, screen, setupTestRouter } from "@kiesraad/test";
+import { ElectionRequestHandler } from "@kiesraad/api-mocks";
+import { expectErrorPage, overrideOnce, Providers, render, screen, server, setupTestRouter } from "@kiesraad/test";
 
 describe("ElectionReportPage", () => {
+  beforeEach(() => {
+    server.use(ElectionRequestHandler);
+  });
+
   test("Error when election is not ready", async () => {
     // Since we test what happens after an error, we want vitest to ignore them
     vi.spyOn(console, "error").mockImplementation(() => {
diff --git a/frontend/app/module/polling_stations/page/PollingStationCreatePage.test.tsx b/frontend/app/module/polling_stations/page/PollingStationCreatePage.test.tsx
index 82f1ca980..bcbb0252e 100644
--- a/frontend/app/module/polling_stations/page/PollingStationCreatePage.test.tsx
+++ b/frontend/app/module/polling_stations/page/PollingStationCreatePage.test.tsx
@@ -2,12 +2,15 @@ import { screen } from "@testing-library/react";
 import { describe, expect, test } from "vitest";
 
 import { ElectionProvider } from "@kiesraad/api";
-import { render } from "@kiesraad/test";
+import { ElectionRequestHandler } from "@kiesraad/api-mocks";
+import { render, server } from "@kiesraad/test";
 
 import { PollingStationCreatePage } from "./PollingStationCreatePage";
 
 describe("PollingStationCreatePage", () => {
   test("Shows form", async () => {
+    server.use(ElectionRequestHandler);
+
     render(
       <ElectionProvider electionId={1}>
         <PollingStationCreatePage />
diff --git a/frontend/app/module/polling_stations/page/PollingStationListPage.test.tsx b/frontend/app/module/polling_stations/page/PollingStationListPage.test.tsx
index 709ebd47d..cd846482b 100644
--- a/frontend/app/module/polling_stations/page/PollingStationListPage.test.tsx
+++ b/frontend/app/module/polling_stations/page/PollingStationListPage.test.tsx
@@ -1,12 +1,17 @@
 import { screen } from "@testing-library/react";
-import { describe, expect, test } from "vitest";
+import { beforeEach, describe, expect, test } from "vitest";
 
 import { PollingStationListPage } from "app/module/polling_stations";
 
 import { ElectionProvider, PollingStationListResponse } from "@kiesraad/api";
-import { overrideOnce, render } from "@kiesraad/test";
+import { ElectionRequestHandler, PollingStationListRequestHandler } from "@kiesraad/api-mocks";
+import { overrideOnce, render, server } from "@kiesraad/test";
 
 describe("PollingStationListPage", () => {
+  beforeEach(() => {
+    server.use(ElectionRequestHandler, PollingStationListRequestHandler);
+  });
+
   test("Show polling stations", async () => {
     render(
       <ElectionProvider electionId={1}>
diff --git a/frontend/app/module/polling_stations/page/PollingStationUpdatePage.test.tsx b/frontend/app/module/polling_stations/page/PollingStationUpdatePage.test.tsx
index 48186682b..58c48353a 100644
--- a/frontend/app/module/polling_stations/page/PollingStationUpdatePage.test.tsx
+++ b/frontend/app/module/polling_stations/page/PollingStationUpdatePage.test.tsx
@@ -1,9 +1,10 @@
 import { within } from "@testing-library/dom";
 import { screen, waitFor } from "@testing-library/react";
 import { userEvent } from "@testing-library/user-event";
-import { describe, expect, test, vi } from "vitest";
+import { beforeEach, describe, expect, test, vi } from "vitest";
 
 import { ElectionProvider, PollingStation } from "@kiesraad/api";
+import { ElectionRequestHandler, PollingStationUpdateHandler } from "@kiesraad/api-mocks";
 import { overrideOnce, render, renderReturningRouter, server } from "@kiesraad/test";
 
 import { PollingStationUpdatePage } from "./PollingStationUpdatePage";
@@ -26,6 +27,10 @@ describe("PollingStationUpdatePage", () => {
     number_of_voters: 1,
   };
 
+  beforeEach(() => {
+    server.use(ElectionRequestHandler, PollingStationUpdateHandler);
+  });
+
   test("Shows form", async () => {
     overrideOnce(
       "get",
diff --git a/frontend/app/routes.test.tsx b/frontend/app/routes.test.tsx
index 5b5d65d08..5d87e6983 100644
--- a/frontend/app/routes.test.tsx
+++ b/frontend/app/routes.test.tsx
@@ -1,8 +1,13 @@
 import { render as rtlRender } from "@testing-library/react";
 import { beforeEach, describe, expect, test, vi } from "vitest";
 
-import { electionStatusMockResponse } from "@kiesraad/api-mocks";
-import { expectErrorPage, expectNotFound, overrideOnce, Providers, setupTestRouter } from "@kiesraad/test";
+import {
+  ElectionListRequestHandler,
+  ElectionRequestHandler,
+  electionStatusMockResponse,
+  ElectionStatusRequestHandler,
+} from "@kiesraad/api-mocks";
+import { expectErrorPage, expectNotFound, overrideOnce, Providers, server, setupTestRouter } from "@kiesraad/test";
 
 import { routes } from "./routes";
 
@@ -14,6 +19,8 @@ const renderWithRouter = () => {
 
 describe("routes", () => {
   beforeEach(() => {
+    server.use(ElectionListRequestHandler, ElectionRequestHandler, ElectionStatusRequestHandler);
+
     // Since we test what happens after an error, we want vitest to ignore them
     vi.spyOn(console, "error").mockImplementation(() => {
       /* do nothing */
diff --git a/frontend/lib/api-mocks/RequestHandlers.ts b/frontend/lib/api-mocks/RequestHandlers.ts
index cab454b3b..3290d92f0 100644
--- a/frontend/lib/api-mocks/RequestHandlers.ts
+++ b/frontend/lib/api-mocks/RequestHandlers.ts
@@ -29,7 +29,7 @@ type PingResponseBody = {
 };
 
 // ping handler for testing
-const pingHandler = http.post<PingParams, PingRequestBody, PingResponseBody>("/ping", async ({ request }) => {
+export const pingHandler = http.post<PingParams, PingRequestBody, PingResponseBody>("/ping", async ({ request }) => {
   const data = await request.json();
 
   const pong = data.ping || "pong";
diff --git a/frontend/lib/api/ApiClient.ts b/frontend/lib/api/ApiClient.ts
index 072dd71fc..3a8954461 100644
--- a/frontend/lib/api/ApiClient.ts
+++ b/frontend/lib/api/ApiClient.ts
@@ -158,8 +158,8 @@ export class ApiClient {
       }
 
       const message = (e as Error).message || "Network error";
-      console.error(e);
-      return new NetworkError(message);
+      console.error(e, method, path);
+      return new NetworkError(`${message}, ${method} ${path}`);
     }
   }
 
diff --git a/frontend/lib/api/api.test.ts b/frontend/lib/api/api.test.ts
index f31c3340c..d328ca9fe 100644
--- a/frontend/lib/api/api.test.ts
+++ b/frontend/lib/api/api.test.ts
@@ -1,11 +1,15 @@
 import { describe, expect, test } from "vitest";
 
+import { pingHandler } from "@kiesraad/api-mocks";
+import { server } from "@kiesraad/test";
+
 type Response = {
   pong: string;
 };
 
 describe("Mock api works", () => {
   test("echos a value", async () => {
+    server.use(pingHandler);
     const resp = await fetch("/ping", {
       method: "POST",
       headers: {
diff --git a/frontend/lib/test/router.ts b/frontend/lib/test/router.ts
deleted file mode 100644
index 7ab5e7b6b..000000000
--- a/frontend/lib/test/router.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { ReactNode } from "react";
-import { createMemoryRouter } from "react-router";
-
-export type Router = ReturnType<typeof createMemoryRouter>;
-
-export function getRouter(children: ReactNode) {
-  return createMemoryRouter([{ path: "*", element: children }]);
-}
diff --git a/frontend/lib/test/router.tsx b/frontend/lib/test/router.tsx
new file mode 100644
index 000000000..dba2712db
--- /dev/null
+++ b/frontend/lib/test/router.tsx
@@ -0,0 +1,15 @@
+/* eslint-disable react-refresh/only-export-components */
+import { ReactNode } from "react";
+import { createMemoryRouter, useRouteError } from "react-router";
+
+export type Router = ReturnType<typeof createMemoryRouter>;
+
+// Render a small html document with the error, for easier vitest debugging
+function ErrorBoundary() {
+  const error = useRouteError() as Error;
+  return <>Error thrown during render: {error.message}</>;
+}
+
+export function getRouter(children: ReactNode) {
+  return createMemoryRouter([{ path: "*", element: children, errorElement: <ErrorBoundary /> }]);
+}
diff --git a/frontend/lib/test/server.ts b/frontend/lib/test/server.ts
index d82052666..a8b6dd60c 100644
--- a/frontend/lib/test/server.ts
+++ b/frontend/lib/test/server.ts
@@ -10,9 +10,7 @@
 import { delay, http, HttpResponse, JsonBodyType } from "msw";
 import { setupServer } from "msw/node";
 
-import { handlers } from "@kiesraad/api-mocks";
-
-export const server = setupServer(...handlers);
+export const server = setupServer();
 
 // Override request handlers in order to test special cases
 export function overrideOnce(