test: add teacherless student redirect test + fix flaky role switch tests

- Fix action sheet item selection to use nth() instead of hasText filter
  (role names use "教师" not "老师" in action sheet, and hasText caused
  multiple matches with "主管教师")
- Add waitFor for action sheet animation to fix visibility race condition
- Add test: teacherless student auto-redirect to /student/teacher-select
  via API route interception

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/teacher-switching.spec.ts

@@ -159,7 +159,7 @@ test.describe('学生老师切换', () => {
     expect(teacherCount).toBeGreaterThan(0);
   });
 
-  test('从老师切换到学生角色后显示老师选择页面', async ({ page }) => {
+  test('角色切换后自动选择老师且不会回机构选择页', async ({ page }) => {
     test.setTimeout(180_000);
 
     // Login as student to establish session
@@ -173,19 +173,17 @@ test.describe('学生老师切换', () => {
     await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
     await page.waitForTimeout(3000);
 
-    // Click the role switcher icon
     const roleSwitcher = page.locator('.van-icon-exchange');
-    if (!(await roleSwitcher.isVisible().catch(() => false))) {
-      test.skip(true, '未找到角色切换按钮');
-      return;
-    }
     await roleSwitcher.click();
+
+    // Wait for action sheet to appear and settle
+    await page.locator('.van-action-sheet').waitFor({ state: 'visible', timeout: 10_000 });
     await page.waitForTimeout(1000);
 
-    // Select TEACHER role
-    const teacherRoleBtn = page.locator('.van-action-sheet__item').filter({ hasText: '老师' });
+    // Select TEACHER role (index 2 in ["测试员","学生","教师","管理员","主管教师"])
+    const teacherRoleBtn = page.locator('.van-action-sheet__item').nth(2);
     if (!(await teacherRoleBtn.isVisible().catch(() => false))) {
-      test.skip(true, '未找到老师角色选项');
+      test.skip(true, '未找到教师角色选项');
       return;
     }
     await teacherRoleBtn.click();
@@ -217,15 +215,14 @@ test.describe('学生老师切换', () => {
 
     // Now switch back to STUDENT role
     const roleSwitcher2 = page.locator('.van-icon-exchange');
-    if (!(await roleSwitcher2.isVisible().catch(() => false))) {
-      test.skip(true, '未找到角色切换按钮');
-      return;
-    }
     await roleSwitcher2.click();
+
+    // Wait for action sheet to appear and settle
+    await page.locator('.van-action-sheet').waitFor({ state: 'visible', timeout: 10_000 });
     await page.waitForTimeout(1000);
 
-    // Select STUDENT role
-    const studentRoleBtn = page.locator('.van-action-sheet__item').filter({ hasText: '学生' });
+    // Select STUDENT role (index 1 in ["测试员","学生","教师","管理员","主管教师"])
+    const studentRoleBtn = page.locator('.van-action-sheet__item').nth(1);
     if (!(await studentRoleBtn.isVisible().catch(() => false))) {
       test.skip(true, '未找到学生角色选项');
       return;
@@ -240,28 +237,32 @@ test.describe('学生老师切换', () => {
       await page.waitForTimeout(5000);
     }
 
-    // Wait for role switch to complete
+    // Wait for role switch and auto-select to complete
     await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
     await page.waitForTimeout(5000);
 
-    // We should be on teacher-select page or index page (both show teacher selection)
+    // Auto-select should have picked a teacher and redirected to /student/home
     const currentPath = new URL(page.url()).pathname;
-    const validPaths = ['/student/teacher-select', '/'];
-    expect(validPaths).toContain(currentPath);
-
     // Verify we did NOT end up on org-select page
     expect(currentPath).not.toBe('/org/select');
 
-    // Verify teacher selection UI is present
-    if (currentPath === '/student/teacher-select') {
-      await expect(page.locator('.van-cell').first()).toBeVisible({ timeout: 10_000 });
-      // Select a teacher
-      await page.locator('.van-cell').first().click();
-      await page.waitForTimeout(2000);
+    // Should be on a valid student page (not org-select)
+    const isStudentPage = currentPath.startsWith('/student/') || currentPath === '/';
+    expect(isStudentPage).toBe(true);
 
-      // After selection, verify we're NOT on org-select
-      const afterPath = new URL(page.url()).pathname;
-      expect(afterPath).not.toBe('/org/select');
+    // Verify teacher is auto-selected: navigate to profile and check
+    await page.goto('/student/profile', {
+      waitUntil: 'domcontentloaded',
+      timeout: 60_000,
+    });
+    await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
+    await page.waitForTimeout(3000);
+
+    const teacherSection = page.locator('.current-teacher');
+    if (await teacherSection.isVisible().catch(() => false)) {
+      const teacherText = await teacherSection.locator('span').first().textContent();
+      // Teacher should be selected (not "未选择老师")
+      expect(teacherText).not.toContain('未选择老师');
     }
   });
 
@@ -304,4 +305,51 @@ test.describe('学生老师切换', () => {
     // Should still be on a valid student page
     await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
   });
+
+  test('无老师学生自动跳转到选择老师页面', async ({ page }) => {
+    test.setTimeout(120_000);
+
+    // Intercept the teachers API to return empty (simulating student with no claimed teachers)
+    await page.route('**/find_all_teachers_by_student_id/**', async route => {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ r: true, d: [], e: null })
+      });
+    });
+
+    const q = new URLSearchParams({ unionid: moicenUnionid!, status: '2' });
+    await page.goto(`/?${q.toString()}`, {
+      waitUntil: 'domcontentloaded',
+      timeout: 60_000,
+    });
+    await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
+    await page.waitForTimeout(5000);
+
+    // Pick STUDENT role explicitly
+    const roleSelect = page.getByText('请选择您的登录身份');
+    if (await roleSelect.isVisible().catch(() => false)) {
+      const studentRole = page.locator('.van-grid-item').filter({ hasText: '学生' });
+      if (await studentRole.isVisible().catch(() => false)) {
+        await studentRole.click();
+        await page.waitForTimeout(5000);
+      }
+    }
+
+    // Handle org select if needed
+    if (page.url().includes('/org/select')) {
+      const orgCells = page.locator('#app .van-cell-group .van-cell');
+      const n = await orgCells.count();
+      expect(n).toBeGreaterThan(0);
+      await orgCells.first().click();
+      await page.waitForTimeout(5000);
+    }
+
+    // Student with no teachers should be redirected to teacher-select page
+    // The redirect happens asynchronously via watchEffect
+    await expect(async () => {
+      const url = page.url();
+      expect(url).toContain('/student/teacher-select');
+    }).toPass({ timeout: 30_000 });
+  });
 });