diff --git a/src/login-web-app/setupTests.ts b/src/login-web-app/setupTests.ts
index a4667743..6a63c6b8 100644
--- a/src/login-web-app/setupTests.ts
+++ b/src/login-web-app/setupTests.ts
@@ -1,6 +1,16 @@
 import '@testing-library/jest-dom/vitest';
 import { vi } from 'vitest';
 
+// bootstrap-configuration.ts throws at import time if window.__CONFIG__ is unset.
+// @ts-expect-error window.__CONFIG__ is not declared on the Window type
+window.__CONFIG__ = {
+  initialUrl: 'https://example.test/auth',
+  haapi: {
+    clientId: 'test-client',
+    tokenEndpoint: 'https://example.test/oauth/token',
+  },
+};
+
 // jsdom doesn't implement <dialog> — minimal mocks for open/close state.
 HTMLDialogElement.prototype.show = vi.fn(function mock(this: HTMLDialogElement) {
   this.open = true;
diff --git a/src/login-web-app/src/haapi-stepper/feature/stepper/HaapiStepper.spec.tsx b/src/login-web-app/src/haapi-stepper/feature/stepper/HaapiStepper.spec.tsx
index 1b04f134..48bc5904 100644
--- a/src/login-web-app/src/haapi-stepper/feature/stepper/HaapiStepper.spec.tsx
+++ b/src/login-web-app/src/haapi-stepper/feature/stepper/HaapiStepper.spec.tsx
@@ -29,7 +29,7 @@ import { act } from 'react';
 import { useHaapiStepper } from './HaapiStepperHook';
 import type { HaapiStepperHistoryEntry, HaapiStepperNextStepAction } from './haapi-stepper.types';
 import { HaapiStepperActionStep, HaapiStepperFormAction } from './haapi-stepper.types';
-import type { BootstrapConfiguration } from '../../data-access/bootstrap-configuration';
+import { configuration } from '../../data-access/bootstrap-configuration';
 
 describe('HaapiStepper', () => {
   const initialStepType = HAAPI_STEPS.AUTHENTICATION;
@@ -53,7 +53,7 @@ describe('HaapiStepper', () => {
         </HaapiStepper>
       );
 
-      expect(mockHaapiFetch).toHaveBeenCalledWith(mockConfiguration.initialUrl, { method: 'GET' });
+      expect(mockHaapiFetch).toHaveBeenCalledWith(configuration.initialUrl, { method: 'GET' });
 
       const stepRendered = await screen.findByTestId('step-type');
 
@@ -714,17 +714,6 @@ vi.mock('../../data-access/haapi-fetch-initializer', () => {
   };
 });
 
-const mockConfiguration: Partial<BootstrapConfiguration> = vi.hoisted(() => {
-  return {
-    initialUrl: 'https://example.com/auth',
-  };
-});
-vi.mock('../../data-access/bootstrap-configuration', () => {
-  return {
-    configuration: mockConfiguration,
-  };
-});
-
 const mockThrowErrorToAppErrorBoundary = vi.fn();
 vi.mock('../../util/useThrowErrorToAppErrorBoundary', () => ({
   // eslint-disable-next-line @eslint-react/hooks-extra/no-unnecessary-use-prefix