"""Tests for AGI-497: SPA/JS-heavy page renders blank. Covers: 1. Skeleton screen detection — many elements but near-zero text triggers a warning in page_stats. 2. Navigate reload fallback — empty-body page triggers retry cycle but ultimately succeeds (no error) because the DOM root exists. Error is only returned when _root is None. """ import asyncio import tempfile import pytest from pytest_httpserver import HTTPServer from browser_use.agent.views import ActionResult from browser_use.browser import BrowserProfile, BrowserSession from browser_use.tools.service import Tools # --------------------------------------------------------------------------- # Fixtures # --------------------------------------------------------------------------- @pytest.fixture(scope='session') def http_server(): """Session-scoped HTTP server for blank-page tests.""" server = HTTPServer() server.start() # --- skeleton page: 30 empty divs, essentially no text --- skeleton_html = 'Loading...' skeleton_html += ''.join(f'

' for i in range(30)) skeleton_html += '' server.expect_request('/skeleton').respond_with_data(skeleton_html, content_type='text/html') # --- rich page: real text content (should NOT be flagged as skeleton) --- server.expect_request('/products').respond_with_data( """ Products

Product Catalog

Widget A

Price: $29.99 - A sturdy widget for everyday use.

Widget B

Price: $49.99 - Premium widget with extended warranty.

Gadget C

Price: $19.50 - Compact gadget, fits in your pocket.

Gadget D

Price: $99.00 - Professional-grade gadget for power users.

""", content_type='text/html', ) # --- empty body page: body is always empty --- # Used to test the navigate retry cycle. _root is NOT None (body element exists), # so navigate retries but ultimately succeeds (no error). server.expect_request('/always-empty').respond_with_data( '', content_type='text/html', ) yield server server.stop() @pytest.fixture(scope='session') def base_url(http_server): return f'http://{http_server.host}:{http_server.port}' @pytest.fixture(scope='module') async def browser_session(): session = BrowserSession( browser_profile=BrowserProfile( headless=True, user_data_dir=None, keep_alive=True, ) ) await session.start() yield session await session.kill() @pytest.fixture(scope='function') def tools(): return Tools() # --------------------------------------------------------------------------- # Helper # --------------------------------------------------------------------------- async def _navigate(tools, browser_session, url): """Navigate to url and give the page a moment to settle.""" await tools.navigate(url=url, new_tab=False, browser_session=browser_session) await asyncio.sleep(0.5) def _make_prompt(state): """Build an AgentMessagePrompt from a BrowserStateSummary using a temp dir for FileSystem.""" from browser_use.agent.prompts import AgentMessagePrompt from browser_use.filesystem.file_system import FileSystem tmp_dir = tempfile.mkdtemp(prefix='browseruse_test_') file_system = FileSystem(base_dir=tmp_dir, create_default_files=False) return AgentMessagePrompt( browser_state_summary=state, file_system=file_system, ) # --------------------------------------------------------------------------- # Test 1: Skeleton screen detection in _extract_page_statistics() # --------------------------------------------------------------------------- class TestSkeletonScreenDetection: """_extract_page_statistics() should flag pages with many elements but very little text.""" async def test_skeleton_page_low_text_chars(self, tools, browser_session, base_url): """Skeleton page: total_elements > 20 but text_chars < total_elements * 5.""" await _navigate(tools, browser_session, f'{base_url}/skeleton') state = await browser_session.get_browser_state_summary(include_screenshot=False) prompt = _make_prompt(state) page_stats = prompt._extract_page_statistics() assert page_stats['total_elements'] > 20, f'Expected >20 elements for skeleton page, got {page_stats["total_elements"]}' assert page_stats['text_chars'] < page_stats['total_elements'] * 5, ( f'Expected text_chars ({page_stats["text_chars"]}) < total_elements*5 ' f'({page_stats["total_elements"] * 5}) for skeleton page' ) async def test_skeleton_page_description_contains_warning(self, tools, browser_session, base_url): """_get_browser_state_description() includes skeleton warning for placeholder pages.""" await _navigate(tools, browser_session, f'{base_url}/skeleton') state = await browser_session.get_browser_state_summary(include_screenshot=False) prompt = _make_prompt(state) description = prompt._get_browser_state_description() assert 'skeleton' in description.lower() or 'placeholder' in description.lower(), ( f'Expected skeleton/placeholder warning in description, got:\n{description[:500]}' ) async def test_rich_page_not_flagged_as_skeleton(self, tools, browser_session, base_url): """A page with real text content should NOT be flagged as skeleton.""" await _navigate(tools, browser_session, f'{base_url}/products') state = await browser_session.get_browser_state_summary(include_screenshot=False) prompt = _make_prompt(state) page_stats = prompt._extract_page_statistics() description = prompt._get_browser_state_description() # Rich page should have substantial text relative to element count assert page_stats['text_chars'] >= page_stats['total_elements'] * 5, ( f'Rich page should have text_chars ({page_stats["text_chars"]}) >= total_elements*5 ' f'({page_stats["total_elements"] * 5})' ) # No skeleton warning in description assert 'skeleton' not in description.lower() and 'placeholder' not in description.lower(), ( 'Rich page should NOT produce a skeleton warning' ) # --------------------------------------------------------------------------- # Test 2: Navigate reload fallback — empty-body page triggers retry but succeeds # --------------------------------------------------------------------------- class TestNavigateReloadFallback: """Navigate retries when llm_representation() is empty, but only errors when _root is None.""" async def test_empty_body_page_retries_then_succeeds(self, tools, browser_session, base_url): """ Navigating to a page with an empty body triggers the health-check retry cycle (empty llm_representation) but ultimately succeeds (no error) because the page HAS a DOM root (_root is not None — the body element exists and is visible). The error path only fires when _root is None (truly unloadable pages like those blocked by anti-bot or returning empty HTTP responses), which avoids false positives on image-only or other non-interactive-but-valid pages. """ empty_url = f'{base_url}/always-empty' # Triggers: health check -> 3s wait -> reload -> 5s wait -> check _root -> not None -> success result = await tools.navigate(url=empty_url, new_tab=False, browser_session=browser_session) assert isinstance(result, ActionResult) # No error — the body IS a valid DOM root, just visually empty. # Skeleton detection (in AgentMessagePrompt._get_browser_state_description) warns the LLM. assert result.error is None, f'Expected no error for empty-body page, got: {result.error}'