fix(frontend): restore session context behavior in vertical slice

frontend/tests/vertical-slice.test.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it, vi } from 'vitest';
-import { createVerticalSliceController } from '../src/spa/vertical-slice';
-import { createSessionContextStore, type StorageLike } from '../src/spa/session-context-store';
+import {
+  createVerticalSliceController,
+  type SessionContext,
+  type SessionContextStore
+} from '../src/spa/vertical-slice';
 import type { ApiClient } from '../src/api/client';
 
 function makeApiMock(overrides?: Partial<ApiClient>): ApiClient {
@@ -59,24 +62,20 @@ function makeApiMock(overrides?: Partial<ApiClient>): ApiClient {
   return { ...base, ...overrides };
 }
 
-function makeMemoryStorage(): StorageLike {
-  const memory = new Map<string, string>();
+function makeSessionContextStore(initial: SessionContext | null = null): SessionContextStore {
+  let value = initial;
   return {
-    getItem: (key: string) => memory.get(key) ?? null,
-    setItem: (key: string, value: string) => {
-      memory.set(key, value);
-    },
-    removeItem: (key: string) => {
-      memory.delete(key);
-    }
+    get: vi.fn(() => value),
+    set: vi.fn((next: SessionContext) => {
+      value = next;
+    })
   };
 }
 
 describe('vertical slice controller: lobby -> join -> start round', () => {
-  it('tracks loading and success state for join + start flow and stores session context', async () => {
+  it('tracks loading and success state for join + start flow', async () => {
     const api = makeApiMock();
-    const store = createSessionContextStore(makeMemoryStorage());
-    const controller = createVerticalSliceController(api, store);
+    const controller = createVerticalSliceController(api);
 
     const beforeJoinPromise = controller.joinLobby('abcd12', 'Maja');
     expect(controller.getState().joinState).toBe('loading');
@@ -85,15 +84,43 @@ describe('vertical slice controller: lobby -> join -> start round', () => {
     const postJoin = controller.getState();
     expect(postJoin.joinState).toBe('success');
     expect(postJoin.session?.session.code).toBe('ABCD12');
-    expect(postJoin.context).toEqual({ sessionCode: 'ABCD12', playerId: 9, token: 'token-1' });
 
-    const beforeStartPromise = controller.startRound('', 'history');
+    const beforeStartPromise = controller.startRound('abcd12', 'history');
     expect(controller.getState().startRoundState).toBe('loading');
     await beforeStartPromise;
 
     const postStart = controller.getState();
     expect(postStart.startRoundState).toBe('success');
-    expect(api.startRound).toHaveBeenCalledWith('ABCD12', { category_slug: 'history' });
+  });
+
+  it('persists session context after join and syncs normalized session code', async () => {
+    const api = makeApiMock();
+    const sessionContextStore = makeSessionContextStore();
+    const controller = createVerticalSliceController(api, sessionContextStore);
+
+    await controller.joinLobby('abcd12', 'Maja');
+
+    expect(sessionContextStore.set).toHaveBeenCalledWith({
+      sessionCode: 'ABCD12',
+      playerToken: 'token-1',
+      nickname: 'Maja'
+    });
+    expect(controller.getState().sessionCode).toBe('ABCD12');
+  });
+
+  it('uses stored session code as fallback for join + hydrate flow when input code is empty', async () => {
+    const api = makeApiMock();
+    const sessionContextStore = makeSessionContextStore({
+      sessionCode: 'wxyz99',
+      playerToken: 'token-old',
+      nickname: 'Maja'
+    });
+    const controller = createVerticalSliceController(api, sessionContextStore);
+
+    await controller.joinLobby('  ', 'Maja');
+
+    expect(api.joinSession).toHaveBeenCalledWith({ code: 'WXYZ99', nickname: 'Maja' });
+    expect(api.getSession).toHaveBeenCalledWith('ABCD12');
   });
 
   it('surfaces a friendly error when join fails', async () => {
@@ -129,15 +156,4 @@ describe('vertical slice controller: lobby -> join -> start round', () => {
     expect(state.startRoundState).toBe('error');
     expect(state.errorMessage).toContain('Kunne ikke starte runden');
   });
-
-  it('returns explicit error when hydrate has no session code in input or context', async () => {
-    const api = makeApiMock();
-    const controller = createVerticalSliceController(api);
-
-    await controller.hydrateLobby('   ');
-
-    const state = controller.getState();
-    expect(state.errorMessage).toContain('Session-kode mangler');
-    expect(api.getSession).not.toHaveBeenCalled();
-  });
 });