test(tools): comprehensive test suite for browser_utils module (+107 tests)

[manus-use]

Summary

Adds a comprehensive test suite for the manus_agent.tools.browser_utils module — 107 fully-mocked tests covering the entire public API surface.

What's tested

Area	Tests	Coverage
BrowserTimeoutError	6	Exception construction, message formatting, attribute access
make_dom_read_script_null_safe	9	All 5 DOM property patterns (textContent, innerText, innerHTML, value, href), empty/unrelated scripts, multiple patterns
normalize_evaluate_script	14	Function/arrow passthrough, expression wrapping, statement block wrapping, empty/whitespace/non-string edge cases
prepare_evaluate_script	3	Combined null-safety + normalization pipeline
normalize_browser_selector	9	Whitespace stripping, quote removal, None/empty/non-string handling, mismatched quotes
is_selector_syntax_error	8	All 6 error marker patterns, false negatives for timeouts/generic errors
is_probably_raw_text_page	8	URL hints (.patch/.diff), content-type detection, pre-only heuristic, rich page rejection, exception handling
extract_raw_page_text	5	pre/body/documentElement fallback chain, all-fail case, empty-string skipping
get_text_with_fallback	10	Primary selector success, fallback chain, timeout propagation, raw-text fallback, syntax error raising, custom timeout
get_html_with_fallback	9	No-selector full page, valid selector inner_html, timeout handling, raw-text detection, syntax errors, custom timeout
find_best_content_selector	5	Priority ordering, short-content skipping, body fallback, exception resilience
extract_page_text	5	Success path, HTML fallback, JS fallback, all-fail error path, URL exception handling
format_browser_error	7	Basic formatting, URL/selector context, Playwright timeout suggestions, empty/no context
Module constants	5	DEFAULT_TIMEOUT, RAW_TEXT_URL_HINTS, FALLBACK_SELECTORS structure validation

Why this module

browser_utils.py (287 lines) is the foundational utility layer for all browser-related tools — it handles timeout management, selector normalization, evaluate script preparation, fallback logic, and raw-text page detection. Despite being imported by both use_browser_patch.py and browser_tools.py, it had virtually zero dedicated test coverage (only a single import reference in test_tools.py).

Testing approach

• 100% mocked — no real browser, Playwright, or HTTP calls
• All async functions tested with pytest.mark.asyncio
• Playwright TimeoutError properly simulated
• Page objects mocked with AsyncMock for realistic async behavior

Open PRs checked (no overlap)

This PR tests browser_utils.py — none of the following open PRs cover this module:

• test(cli): comprehensive test suite for is_complex_task, display_task_plan, and _make_agent (+80 tests) #152 (cli dispatch helpers), test(multi_agents): comprehensive test suite for orchestrator, workflow agent, and data types (+73 tests) #151 (multi_agents), test(tools): comprehensive test suite for manus_workflow module (+58 tests) #150 (manus_workflow), test(tools): comprehensive test suite for workflow_tool module (+60 tests) #148 (workflow_tool), test(tools): comprehensive test suite for verify_exploit tool function (+49 tests) #145 (verify_exploit), test(sandbox): comprehensive test suite for exploit_sandbox module (+76 tests) #144 (exploit_sandbox), test(sandbox): comprehensive test suite for docker_sandbox module (+69 tests) #143 (docker_sandbox), test(utils): comprehensive test suite for docker_client module (+84 tests) #142 (docker_client), test(tools): comprehensive test suite for code_execute module (+45 tests) #141 (code_execute), test(tools): comprehensive test suite for http_request truncation wrapper (+36 tests) #140 (http_request truncation)

Test results

1265 passed, 3 deselected, 3 warnings in 24.50s

(Baseline: 1158 + 107 new = 1265 total, 0 failures)