diff --git a/src/api.test.ts b/src/api.test.ts
index 8cc0694..18a5ced 100644
--- a/src/api.test.ts
+++ b/src/api.test.ts
@@ -1,11 +1,26 @@
 import { applyMiddleware, legacy_createStore as createStore } from 'redux';
 import { thunk } from 'redux-thunk';
 
-import { requestLogin, requestUserData } from '@/api';
+import {
+  requestDeleteUser,
+  requestLogin,
+  requestRegisterUser,
+  requestStripePaymentSheet,
+  requestUserData,
+} from '@/api';
 import rootReducer from '@/reducers';
 
 const createTestStore = () => createStore(rootReducer, undefined, applyMiddleware(thunk));
 
+const fetchMock = global.fetch as jest.Mock;
+
+const mockResponseOnce = (json: unknown, ok = true) =>
+  fetchMock.mockResolvedValueOnce({ ok, status: ok ? 200 : 400, json: async () => json });
+
+beforeEach(() => {
+  fetchMock.mockClear();
+});
+
 describe('dev fake users (__DEV__ only)', () => {
   it.each([
     ['nonmember', false],
@@ -22,3 +37,187 @@ describe('dev fake users (__DEV__ only)', () => {
     expect(global.fetch).not.toHaveBeenCalled();
   });
 });
+
+describe('requestLogin', () => {
+  it('posts credentials and stores the token on success', async () => {
+    const store = createTestStore();
+    mockResponseOnce({ token: 'token-123' });
+
+    await store.dispatch(requestLogin('grisen', 'hunter2'));
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://dusken.example.test/auth/obtain-token/',
+      expect.objectContaining({
+        method: 'POST',
+        body: JSON.stringify({ username: 'grisen', password: 'hunter2' }),
+      }),
+    );
+    expect(store.getState()).toMatchObject({
+      isAuthenticated: true,
+      isLoggingIn: false,
+      userToken: 'token-123',
+      loginError: null,
+    });
+  });
+
+  it('stores the API error body on a rejected login', async () => {
+    jest.spyOn(console, 'log').mockImplementation(() => {});
+    const store = createTestStore();
+    const apiError = { non_field_errors: ['Kan ikke logge inn med disse opplysningene'] };
+    mockResponseOnce(apiError, false);
+
+    await store.dispatch(requestLogin('grisen', 'wrong-password'));
+
+    expect(store.getState()).toMatchObject({
+      isAuthenticated: false,
+      isLoggingIn: false,
+      userToken: null,
+      loginError: apiError,
+    });
+  });
+
+  it('falls back to a generic error message when the API returns an empty body', async () => {
+    jest.spyOn(console, 'log').mockImplementation(() => {});
+    const store = createTestStore();
+    mockResponseOnce(null, false);
+
+    await store.dispatch(requestLogin('grisen', 'hunter2'));
+
+    expect(store.getState().loginError).toEqual({ non_field_errors: ['Kunne ikke logge inn, prøv igjen'] });
+  });
+});
+
+describe('requestUserData', () => {
+  it('fetches /api/me/ with the auth token and stores the user', async () => {
+    const store = createTestStore();
+    const user = { username: 'grisen', email: 'grisen@example.test', is_member: true };
+    mockResponseOnce(user);
+
+    await store.dispatch(requestUserData('token-123'));
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://dusken.example.test/api/me/',
+      expect.objectContaining({
+        method: 'GET',
+        headers: expect.objectContaining({ Authorization: 'Token token-123' }),
+      }),
+    );
+    expect(store.getState()).toMatchObject({ isFetchingUserData: false, user });
+  });
+
+  it('stores the API error body when fetching user data fails', async () => {
+    const store = createTestStore();
+    const apiError = { detail: 'Ugyldig token.' };
+    mockResponseOnce(apiError, false);
+
+    await store.dispatch(requestUserData('expired-token'));
+
+    expect(store.getState()).toMatchObject({ isFetchingUserData: false, user: null, userError: apiError });
+  });
+});
+
+describe('requestRegisterUser', () => {
+  const formValues = {
+    first_name: 'Grisen',
+    last_name: 'Testersen',
+    email: 'grisen@example.test',
+    phone_number: '+4712345678',
+    password: 'hunter2',
+  };
+
+  it('authenticates with the returned auth_token and stores the user without it', async () => {
+    const store = createTestStore();
+    mockResponseOnce({ username: 'grisen', email: 'grisen@example.test', auth_token: 'token-456' });
+
+    await store.dispatch(requestRegisterUser(formValues));
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://dusken.example.test/api/user/register/',
+      expect.objectContaining({ method: 'POST', body: JSON.stringify(formValues) }),
+    );
+    expect(store.getState()).toMatchObject({
+      isRegisteringUser: false,
+      isAuthenticated: true,
+      userToken: 'token-456',
+      user: { username: 'grisen', email: 'grisen@example.test' },
+    });
+    expect(store.getState().user).not.toHaveProperty('auth_token');
+  });
+
+  it('stores field errors from the API when registration fails', async () => {
+    const store = createTestStore();
+    const apiError = { email: ['Denne e-postadressen er allerede i bruk'] };
+    mockResponseOnce(apiError, false);
+
+    await store.dispatch(requestRegisterUser(formValues));
+
+    expect(store.getState()).toMatchObject({
+      isRegisteringUser: false,
+      isAuthenticated: false,
+      registerError: apiError,
+    });
+  });
+});
+
+describe('requestDeleteUser', () => {
+  it('resets the store to its initial state on success', async () => {
+    const store = createTestStore();
+    // Authenticate first (via the fake-user shortcut) so the reset is observable
+    await store.dispatch(requestLogin('member', 'any-password'));
+    expect(store.getState().isAuthenticated).toBe(true);
+
+    mockResponseOnce({});
+    await store.dispatch(requestDeleteUser('token-123'));
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://dusken.example.test/api/me/delete/',
+      expect.objectContaining({
+        method: 'DELETE',
+        headers: expect.objectContaining({ Authorization: 'Token token-123' }),
+      }),
+    );
+    expect(store.getState()).toMatchObject({ isAuthenticated: false, userToken: null, user: null });
+  });
+
+  it('stores the API error body when deletion fails', async () => {
+    const store = createTestStore();
+    const apiError = { detail: 'Kan ikke slette bruker med aktivt medlemskap' };
+    mockResponseOnce(apiError, false);
+
+    await store.dispatch(requestDeleteUser('token-123'));
+
+    expect(store.getState()).toMatchObject({ isDeletingUser: false, deleteUserError: apiError });
+  });
+});
+
+describe('requestStripePaymentSheet', () => {
+  it('posts the membership type and returns the payment sheet parameters', async () => {
+    const sheet = { paymentIntent: 'pi_secret', ephemeralKey: 'ek_secret', customer: 'cus_123' };
+    mockResponseOnce(sheet);
+
+    await expect(requestStripePaymentSheet('token-123', 'standard')).resolves.toEqual(sheet);
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://dusken.example.test/api/stripe/payment-sheet/',
+      expect.objectContaining({
+        method: 'POST',
+        body: JSON.stringify({ membership_type: 'standard' }),
+        headers: expect.objectContaining({ Authorization: 'Token token-123' }),
+      }),
+    );
+  });
+
+  it('rejects with the API detail message on failure', async () => {
+    mockResponseOnce({ detail: 'Ugyldig medlemskapstype' }, false);
+
+    await expect(requestStripePaymentSheet('token-123', 'bogus')).rejects.toThrow('Ugyldig medlemskapstype');
+  });
+
+  it('rejects with a generic message when the API gives no detail', async () => {
+    mockResponseOnce({}, false);
+
+    await expect(requestStripePaymentSheet('token-123', 'standard')).rejects.toThrow(
+      'Kunne ikke belaste bankkortet, prøv igjen',
+    );
+  });
+});
diff --git a/src/api.ts b/src/api.ts
index e2c89cf..e382da1 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -212,7 +212,7 @@ export async function requestStripePaymentSheet(authToken: string, membershipTyp
         return data;
       },
       (data) => {
-        return data.detail || 'Kunne ikke belaste bankkortet, prøv igjen';
+        throw new Error(data?.detail || 'Kunne ikke belaste bankkortet, prøv igjen');
       },
     );
 }
diff --git a/src/components/FormInput.tsx b/src/components/FormInput.tsx
index af236bf..4f7adf5 100644
--- a/src/components/FormInput.tsx
+++ b/src/components/FormInput.tsx
@@ -36,6 +36,7 @@ const FormInput = ({
           <TextField
             ref={ref}
             label={<Text style={theme.text}>{label}</Text>}
+            accessibilityLabel={label}
             returnKeyType={returnKeyType}
             onChangeText={onChange}
             onBlur={onBlur}
diff --git a/src/modules/membership/Proof.test.tsx b/src/modules/membership/Proof.test.tsx
new file mode 100644
index 0000000..34a5978
--- /dev/null
+++ b/src/modules/membership/Proof.test.tsx
@@ -0,0 +1,180 @@
+import { gql } from '@apollo/client';
+import { fireEvent, waitFor } from '@testing-library/react-native';
+import * as Notifications from 'expo-notifications';
+import React from 'react';
+
+import Proof from '@/modules/membership/Proof';
+import { renderWithProviders, testUser } from '@/testUtils';
+import type { UserType } from '@/types/data';
+
+// The setup-wide stripe mock resolves initPaymentSheet/presentPaymentSheet
+// with { error: null }; useStripe() hands out these same jest.fn instances.
+const { initPaymentSheet, presentPaymentSheet } = jest.requireMock('@stripe/stripe-react-native') as {
+  initPaymentSheet: jest.Mock;
+  presentPaymentSheet: jest.Mock;
+};
+
+const fetchMock = global.fetch as jest.Mock;
+
+const mockPaymentSheetResponse = () =>
+  fetchMock.mockResolvedValueOnce({
+    ok: true,
+    status: 200,
+    json: async () => ({ paymentIntent: 'pi_secret', ephemeralKey: 'ek_secret', customer: 'cus_123' }),
+  });
+
+// Must match PROOF_QUERY in useProof.tsx
+const PROOF_QUERY = gql`
+  {
+    membershipTypes {
+      slug
+      price
+    }
+  }
+`;
+
+const apolloMocks = [
+  {
+    request: { query: PROOF_QUERY },
+    result: {
+      data: {
+        membershipTypes: [
+          { __typename: 'MembershipType', slug: 'student', price: 15000 },
+          { __typename: 'MembershipType', slug: 'regular', price: 30000 },
+          { __typename: 'MembershipType', slug: 'support', price: 50000 },
+        ],
+      },
+    },
+  },
+];
+
+const nonMember: UserType = { ...testUser, is_member: false, last_membership: null };
+
+const expiredMember: UserType = {
+  ...testUser,
+  is_member: false,
+  last_membership: { membership_type: 'standard', end_date: '2020-01-01' },
+};
+
+const renderProof = ({ user = nonMember, fetchUser = jest.fn() }: { user?: UserType; fetchUser?: () => void } = {}) =>
+  renderWithProviders(
+    <Proof onLogoutPress={jest.fn()} fetchUser={fetchUser} isFetchingUserData={false} onDeletePress={jest.fn()} />,
+    {
+      preloadedState: { isAuthenticated: true, userToken: 'test-token', user },
+      apolloMocks,
+    },
+  );
+
+beforeEach(() => {
+  jest.clearAllMocks();
+  (Notifications.getPermissionsAsync as jest.Mock).mockResolvedValue({ status: 'undetermined' });
+});
+
+it('purchases the preselected membership through the stripe payment sheet', async () => {
+  mockPaymentSheetResponse();
+  const { findByText } = renderProof();
+
+  // 'Ordinær' (slug: regular) is preselected; the button enables once the
+  // membership type query has resolved and its price is shown
+  fireEvent.press(await findByText('Kjøp medlemskap (300 NOK)'));
+
+  expect(await findByText('Your order is confirmed!')).toBeTruthy();
+  expect(fetchMock).toHaveBeenCalledWith(
+    'https://dusken.example.test/api/stripe/payment-sheet/',
+    expect.objectContaining({
+      method: 'POST',
+      body: JSON.stringify({ membership_type: 'regular' }),
+      headers: expect.objectContaining({ Authorization: 'Token test-token' }),
+    }),
+  );
+  expect(initPaymentSheet).toHaveBeenCalledWith(
+    expect.objectContaining({
+      paymentIntentClientSecret: 'pi_secret',
+      customerEphemeralKeySecret: 'ek_secret',
+      customerId: 'cus_123',
+      defaultBillingDetails: expect.objectContaining({
+        email: testUser.email,
+        name: 'Test Testesen',
+      }),
+    }),
+  );
+  expect(presentPaymentSheet).toHaveBeenCalled();
+});
+
+it('purchases the selected membership type, not the default', async () => {
+  mockPaymentSheetResponse();
+  const { findByText, getByText } = renderProof();
+
+  fireEvent.press(await findByText('Student'));
+  fireEvent.press(getByText('Kjøp medlemskap (150 NOK)'));
+
+  expect(await findByText('Your order is confirmed!')).toBeTruthy();
+  expect(fetchMock).toHaveBeenCalledWith(
+    'https://dusken.example.test/api/stripe/payment-sheet/',
+    expect.objectContaining({ body: JSON.stringify({ membership_type: 'student' }) }),
+  );
+});
+
+it('shows the stripe error when the payment sheet is not completed', async () => {
+  mockPaymentSheetResponse();
+  presentPaymentSheet.mockResolvedValueOnce({
+    error: { code: 'Canceled', message: 'The payment flow has been canceled' },
+  });
+  const { findByText, queryByText } = renderProof();
+
+  fireEvent.press(await findByText('Kjøp medlemskap (300 NOK)'));
+
+  expect(await findByText('Error code: Canceled The payment flow has been canceled')).toBeTruthy();
+  expect(queryByText('Your order is confirmed!')).toBeNull();
+});
+
+it('shows an error and does not present the sheet when the backend rejects the purchase', async () => {
+  jest.spyOn(console, 'error').mockImplementation(() => {});
+  fetchMock.mockResolvedValueOnce({
+    ok: false,
+    status: 400,
+    json: async () => ({ detail: 'Ugyldig medlemskapstype' }),
+  });
+  const { findByText, getByRole } = renderProof();
+
+  fireEvent.press(await findByText('Kjøp medlemskap (300 NOK)'));
+
+  expect(await findByText('Oops! Could not initialise payment')).toBeTruthy();
+  expect(initPaymentSheet).not.toHaveBeenCalled();
+  expect(presentPaymentSheet).not.toHaveBeenCalled();
+  // The purchase button recovers so the user can retry
+  expect(getByRole('button', { name: 'Kjøp medlemskap (300 NOK)' })).toBeEnabled();
+});
+
+it('shows an error and does not present the sheet when stripe fails to initialise it', async () => {
+  jest.spyOn(console, 'error').mockImplementation(() => {});
+  mockPaymentSheetResponse();
+  initPaymentSheet.mockResolvedValueOnce({ error: { code: 'Failed', message: 'Invalid client secret' } });
+  const { findByText } = renderProof();
+
+  fireEvent.press(await findByText('Kjøp medlemskap (300 NOK)'));
+
+  expect(await findByText('Oops! Could not initialise payment')).toBeTruthy();
+  expect(presentPaymentSheet).not.toHaveBeenCalled();
+});
+
+it('refetches user data when the stored membership has expired', async () => {
+  const fetchUser = jest.fn();
+  renderProof({ user: expiredMember, fetchUser });
+
+  await waitFor(() => expect(fetchUser).toHaveBeenCalled());
+  // Notification permission was never granted, so nothing is scheduled
+  expect(Notifications.scheduleNotificationAsync).not.toHaveBeenCalled();
+});
+
+it('cancels stale expiry notifications when permission is granted, without scheduling one in the past', async () => {
+  (Notifications.getPermissionsAsync as jest.Mock).mockResolvedValue({ status: 'granted' });
+  const fetchUser = jest.fn();
+  renderProof({ user: expiredMember, fetchUser });
+
+  // Once the granted permission resolves, the expiry effect runs the cleanup
+  await waitFor(() => expect(Notifications.cancelAllScheduledNotificationsAsync).toHaveBeenCalled());
+  expect(fetchUser).toHaveBeenCalled();
+  // The expiry date is in the past, so no new notification is scheduled
+  expect(Notifications.scheduleNotificationAsync).not.toHaveBeenCalled();
+});
diff --git a/src/modules/membership/useProof.tsx b/src/modules/membership/useProof.tsx
index 3a4d076..b17b173 100644
--- a/src/modules/membership/useProof.tsx
+++ b/src/modules/membership/useProof.tsx
@@ -38,11 +38,14 @@ const useProof = ({ fetchUser }: UseProofProps) => {
     )?.price ?? 25000;
 
   const openPaymentSheet = async () => {
+    setPaymentLoading(true);
     try {
       await initializePaymentSheet();
     } catch (err) {
       console.error('🔥', err);
       setToast({ message: 'Oops! Could not initialise payment', visible: true, preset: 'failure' });
+      setPaymentLoading(false);
+      return;
     }
     const { error } = await presentPaymentSheet();
     const message = error ? `Error code: ${error.code} ${error.message}` : 'Your order is confirmed!';
@@ -51,7 +54,6 @@ const useProof = ({ fetchUser }: UseProofProps) => {
   };
 
   const initializePaymentSheet = async () => {
-    setPaymentLoading(true);
     const { paymentIntent, ephemeralKey, customer } = await requestStripePaymentSheet(
       userToken as string,
       membershipTypeSlug,
@@ -71,8 +73,8 @@ const useProof = ({ fetchUser }: UseProofProps) => {
       },
       returnURL: `${Constants.expoConfig?.scheme}://stripe-redirect`,
     });
-    if (!error) {
-      setPaymentLoading(true);
+    if (error) {
+      throw error;
     }
   };
 
diff --git a/src/modules/register/UserRegister.test.tsx b/src/modules/register/UserRegister.test.tsx
index 4e6e31c..714ec3f 100644
--- a/src/modules/register/UserRegister.test.tsx
+++ b/src/modules/register/UserRegister.test.tsx
@@ -1,8 +1,40 @@
+import { fireEvent, waitFor, type RenderResult } from '@testing-library/react-native';
 import React from 'react';
 
 import UserRegister from '@/modules/register/UserRegister';
 import { renderWithProviders } from '@/testUtils';
 
+// The screen is pushed on top of Login and closes itself with goBack() once
+// registration succeeds; stub the navigation object so we can assert on that.
+const mockGoBack = jest.fn();
+jest.mock('@react-navigation/native', () => {
+  const actual = jest.requireActual('@react-navigation/native');
+  return { ...actual, useNavigation: () => ({ goBack: mockGoBack }) };
+});
+
+const fetchMock = global.fetch as jest.Mock;
+
+const mockResponseOnce = (json: unknown, ok = true) =>
+  fetchMock.mockResolvedValueOnce({ ok, status: ok ? 200 : 400, json: async () => json });
+
+const validFormValues: Record<string, string> = {
+  Fornavn: 'Grisen',
+  Etternavn: 'Testesen',
+  'E-post': 'grisen@example.test',
+  Mobilnummer: '+4712345678',
+  Passord: 'hunter2',
+};
+
+const fillForm = (getByLabelText: RenderResult['getByLabelText'], overrides: Record<string, string> = {}) => {
+  Object.entries({ ...validFormValues, ...overrides }).forEach(([label, value]) => {
+    fireEvent.changeText(getByLabelText(label), value);
+  });
+};
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
 it('renders the registration form', () => {
   const { getByText } = renderWithProviders(<UserRegister />);
 
@@ -10,3 +42,63 @@ it('renders the registration form', () => {
   expect(getByText('E-post')).toBeTruthy();
   expect(getByText('Registrer meg')).toBeTruthy();
 });
+
+it('disables the submit button while the form is incomplete', () => {
+  const { getByText, getByRole, store } = renderWithProviders(<UserRegister />);
+
+  expect(getByRole('button', { name: 'Registrer meg' })).toBeDisabled();
+  fireEvent.press(getByText('Registrer meg'));
+
+  expect(fetchMock).not.toHaveBeenCalled();
+  expect(store.getState().isRegisteringUser).toBe(false);
+});
+
+it('submits the form, authenticates and navigates back on success', async () => {
+  mockResponseOnce({ username: 'grisen', email: 'grisen@example.test', auth_token: 'token-456' });
+  const { getByText, getByRole, getByLabelText, store } = renderWithProviders(<UserRegister />);
+
+  fillForm(getByLabelText);
+  await waitFor(() => expect(getByRole('button', { name: 'Registrer meg' })).toBeEnabled());
+  fireEvent.press(getByText('Registrer meg'));
+
+  await waitFor(() => expect(store.getState().isAuthenticated).toBe(true));
+  expect(fetchMock).toHaveBeenCalledWith(
+    'https://dusken.example.test/api/user/register/',
+    expect.objectContaining({
+      method: 'POST',
+      body: JSON.stringify({
+        first_name: 'Grisen',
+        last_name: 'Testesen',
+        email: 'grisen@example.test',
+        phone_number: '+4712345678',
+        password: 'hunter2',
+      }),
+    }),
+  );
+  expect(store.getState().userToken).toBe('token-456');
+  expect(mockGoBack).toHaveBeenCalled();
+});
+
+it('shows server field errors on the matching form field', async () => {
+  mockResponseOnce({ email: ['Denne e-postadressen er allerede i bruk'] }, false);
+  const { getByText, getByRole, getByLabelText, findByText, store } = renderWithProviders(<UserRegister />);
+
+  fillForm(getByLabelText);
+  await waitFor(() => expect(getByRole('button', { name: 'Registrer meg' })).toBeEnabled());
+  fireEvent.press(getByText('Registrer meg'));
+
+  expect(await findByText('Denne e-postadressen er allerede i bruk')).toBeTruthy();
+  expect(store.getState().isAuthenticated).toBe(false);
+  expect(mockGoBack).not.toHaveBeenCalled();
+});
+
+it('rejects an invalid e-mail address without hitting the network', async () => {
+  const { getByLabelText, findByText } = renderWithProviders(<UserRegister />);
+
+  fillForm(getByLabelText, { 'E-post': 'not-an-email' });
+  // Enter on the last field submits too, bypassing the disabled button
+  fireEvent(getByLabelText('Passord'), 'submitEditing');
+
+  expect(await findByText('er ikke en gyldig e-post')).toBeTruthy();
+  expect(fetchMock).not.toHaveBeenCalled();
+});
diff --git a/src/modules/register/useUserRegister.tsx b/src/modules/register/useUserRegister.tsx
index 91c2ed4..363f268 100644
--- a/src/modules/register/useUserRegister.tsx
+++ b/src/modules/register/useUserRegister.tsx
@@ -64,8 +64,8 @@ const useUserRegister = () => {
   }, [isAuthenticatedPrev, isAuthenticated, navigation]);
 
   useEffect(() => {
-    clearErrors();
     if (!isSubmitted || !registerError) return;
+    clearErrors();
     Object.keys(registerError).forEach((key) => {
       const errorMessages = registerError[key];
       if (!errorMessages || !Array.isArray(errorMessages)) {
diff --git a/src/reduxStore.ts b/src/reduxStore.ts
index 0689c62..de6540e 100644
--- a/src/reduxStore.ts
+++ b/src/reduxStore.ts
@@ -9,6 +9,10 @@ const persistConfig = {
   key: 'root',
   storage: AsyncStorage,
   blacklist: ['isLoggingIn', 'isFetchingUserData', 'isRegisteringUser', 'loginError'],
+  // redux-persist never clears its 5s rehydration-watchdog timer, which keeps
+  // Jest workers alive after tests finish; 0 disables it. The mocked
+  // AsyncStorage rehydrates instantly, so the watchdog protects nothing there.
+  timeout: process.env.NODE_ENV === 'test' ? 0 : undefined,
 };
 
 const persistedReducer = persistReducer(persistConfig, rootReducer);