Browser Testing

Browser Automation — ABP

Single tool: {baseDir}/browser.js <command> [args] [--flags]

ABP is a Chromium fork with a REST API baked into the engine. Every action is atomic — JS freezes between steps, no race conditions, no manual waits.

How ABP Works (Execution Model)

ABP pauses JavaScript and virtual time between your actions. The page is frozen until the next command.

Each action triggers a 3-phase settle cycle:

1. Pre-network wait (150ms) — JS fires handlers from your action
2. Network tracking — waits for triggered requests to complete (up to 1s timeout)
3. Post-settle (350ms) — DOM stabilizes after network responses

One command = resume → dispatch action → settle → screenshot (if requested) → re-pause.

This means: no sleep() hacks, no race conditions, no flaky selectors. If a click triggers an API call, ABP waits for it automatically.

Setup

{baseDir}/browser.js start           # Launch ABP (auto-port per project)
{baseDir}/browser.js port            # Show resolved port

Port Management

Each project gets its own ABP instance automatically — no config needed.

Port is derived deterministically from git root path → range 9222–19221. Same project = same port. Different project = different port.

Override: --port 8222 (any command) or ABP_PORT=8222 env var.

Launch Options

All flags below apply to start and are forwarded to ABP:

B={baseDir}/browser.js

$B start --headless                  # No visible window
$B start --user-data-dir /tmp/prof   # Chrome profile directory
$B start --profile-directory Default # Profile name within user-data-dir
$B start --user-agent "MyBot/1.0"    # Custom User-Agent
$B start --zoom 1.5                  # Zoom level
$B start --verbose                   # Pipe browser output to stderr
$B start --session-dir ./my-session  # Session data directory
$B start --config-file ./abp.json    # ABP JSON config
$B start --disable-pause             # Don't freeze JS between actions

# Settlement tuning (for slow apps)
$B start --min-wait 500              # Pre-network wait (default: 150ms)
$B start --tracking-timeout 3000     # Network tracking timeout (default: 1000ms)
$B start --post-settle 1000          # Post-network settle (default: 350ms)

# Pass Chrome flags
$B start --chrome-args --disable-gpu,--no-sandbox

Core Commands

B={baseDir}/browser.js

# Navigate
$B nav https://example.com           # Navigate active tab
$B nav https://other.com --new       # New tab
$B back                              # History back
$B forward                           # History forward
$B reload                            # Reload

# Mouse
$B click 450 320                     # Left click
$B click 450 320 --right             # Right click
$B click 450 320 --double            # Double click
$B click 450 320 --mod CTRL          # Ctrl+click
$B hover 300 200                     # Mouse move (trigger tooltips/menus)
$B scroll 640 400 --dy 500           # Scroll down 500px
$B scroll 640 400 --dy -300          # Scroll up
$B scroll 640 400 --dx 200           # Scroll right
$B drag 100 200 500 200              # Drag from→to
$B drag 100 200 500 200 --steps 20   # Smooth drag

# Keyboard
$B type hello world                  # Type text
$B key ENTER                         # Press key
$B key TAB                           # Tab
$B key ESCAPE                        # Escape
$B key a --mod CTRL                  # Ctrl+A (select all)
$B key c --mod CTRL                  # Ctrl+C (copy)
$B key ARROWDOWN                     # Arrow keys
$B key BACKSPACE
$B key a --mod CTRL --action down    # Key down only (hold)
$B key a --action up                 # Key up (release)

# Input helpers
$B slider 400 300 75                 # Set range input to 75
$B clear 400 300                     # Clear text field (click + select all + delete)
$B pick "Select the login button"    # Interactive: user clicks element in browser

# Observe / Assert / Watch (prefer these — low token cost)
$B observe                           # Structured page snapshot (~150 tokens)
$B observe "form"                    # Scoped to CSS selector (~50 tokens)
$B observe --shot                    # Structured data + screenshot in one call
$B assert text "Welcome"             # Pass/fail text check (~20 tokens)
$B assert selector "#dashboard"      # Element exists?
$B assert url "/dashboard"           # URL contains?
$B assert title "Dashboard"          # Title contains?
$B watch --text "Done" --timeout 30000   # Wait for async result
$B watch --selector ".loaded"        # Wait for element to appear
$B watch --eval "items.length > 5"   # Wait for JS condition
$B watch --text "Done" --shot        # Wait + screenshot on match

# Screenshot (only when you need to see layout/visuals)
$B screenshot                        # Viewport with interactive markup
$B fullpage                          # Full-page screenshot (scroll + stitch, pure Deno)
$B screenshot --markup clickable     # Only clickable elements highlighted
$B screenshot --markup typeable      # Only input fields highlighted
$B screenshot --markup none          # Clean, no overlays
$B screenshot --format png           # PNG instead of WebP

# Extract content
$B text                              # All visible text (fast, API-native)
$B text "h1.title"                   # Text within CSS selector
$B eval 'document.title'             # Execute JavaScript
$B eval '({links: document.querySelectorAll("a").length})'
$B content                           # Current page as Markdown (Readability)
$B content https://example.com       # Navigate + extract as Markdown
$B cookies                           # Non-HttpOnly cookies

Waiting & Network

$B wait 2000                         # Wait 2s (resumes JS during wait)
$B network                           # Wait for pending network requests to settle

network is useful after actions that trigger slow API calls — when the 1s default tracking timeout isn't enough. It re-runs the settle cycle without performing any action.

Console & Error Capture

ABP doesn't expose DevTools console natively, but you can inject capture:

$B console install                   # Inject console.log/warn/error/info/debug capture
$B console drain                     # Retrieve all captured logs (clears buffer)
$B console clear                     # Clear buffer without reading

# Output format:
# · [log] User loaded profile
# ⚠ [warn] Deprecated API call
# ✗ [error] Failed to fetch /api/data
# 💥 [exception] TypeError: Cannot read property 'x' of null at app.js:42
# 💥 [rejection] Unhandled promise rejection: NetworkError

Install once after navigation, then drain periodically. Captures console.*, uncaught exceptions, and unhandled promise rejections.

Deep Browser Access via eval

eval gives full access to the page's JS context — any Web API, any DOM operation:

# DOM inspection
$B eval 'document.querySelectorAll("form").length'
$B eval 'document.querySelector("#app").__vue__'          # Vue internals
$B eval 'document.querySelector("#root")._reactRootContainer'  # React fiber

# localStorage / sessionStorage
$B eval 'JSON.stringify(Object.fromEntries(Object.entries(localStorage)))'
$B eval 'sessionStorage.getItem("auth_token")'

# Service Workers
$B eval 'navigator.serviceWorker.getRegistrations().then(r => r.map(sw => sw.scope))'

# IndexedDB databases
$B eval 'indexedDB.databases().then(dbs => dbs.map(d => d.name))'

# Geolocation (mock via permission grant, or query)
$B eval 'new Promise(r => navigator.geolocation.getCurrentPosition(p => r(p.coords)))'

# Clipboard
$B eval 'navigator.clipboard.readText()'

# Page visibility / focus
$B eval '({ hidden: document.hidden, focused: document.hasFocus(), visibility: document.visibilityState })'

# Computed styles
$B eval 'getComputedStyle(document.querySelector(".btn")).backgroundColor'

# Accessibility tree
$B eval 'document.querySelector("main").getAttribute("role")'

Gotcha: eval uses global scope — const/let redeclarations fail on second call. Wrap in IIFE: (() => { ... })()

Network Analysis

Use performance.getEntriesByType('resource') via eval to audit network requests after page load. Navigate, wait 5-8s for hydration, then eval.

# Count requests by category
$B eval "
(() => {
  const e = performance.getEntriesByType('resource');
  const apis = e.filter(r => r.name.includes('/api/'));
  return 'total=' + e.length + ' api=' + apis.length + '\\n' +
    apis.map(r => r.name.replace(/https?:\/\/[^/]+/,'').split('?')[0] +
    ' ' + Math.round(r.duration) + 'ms ' + (r.transferSize||0) + 'B').join('\\n');
})()
"

# Full breakdown by type
$B eval "
(() => {
  const e = performance.getEntriesByType('resource');
  const c = {};
  for (const r of e) {
    const u = r.name;
    let k = 'other';
    if (u.includes('/api/')) k = 'API';
    else if (u.includes('.js')) k = 'JS';
    else if (u.includes('.css')) k = 'CSS';
    else if (u.match(/\.(png|jpg|webp|svg|gif)/)) k = 'Images';
    else if (u.includes('.woff')) k = 'Fonts';
    if (!c[k]) c[k] = [0, 0];
    c[k][0]++;
    c[k][1] += r.transferSize || 0;
  }
  return JSON.stringify(c);
})()
"

# Monitor XHR/fetch in real-time (inject, then drain)
$B eval "
(() => {
  if (window.__abpNet) return 'already installed';
  window.__abpNet = [];
  const origFetch = window.fetch;
  window.fetch = async (...args) => {
    const url = typeof args[0] === 'string' ? args[0] : args[0]?.url || '?';
    const method = args[1]?.method || 'GET';
    const start = Date.now();
    try {
      const r = await origFetch(...args);
      window.__abpNet.push({ url, method, status: r.status, ms: Date.now()-start });
      return r;
    } catch(e) {
      window.__abpNet.push({ url, method, error: e.message, ms: Date.now()-start });
      throw e;
    }
  };
  return 'installed';
})()
"

# Drain captured fetch calls
$B eval "(() => { const n = window.__abpNet || []; window.__abpNet = []; return JSON.stringify(n); })()"

Common gotchas:

• transferSize=0 means cache hit (CF, browser, or service worker)
• Resources appear incrementally — wait 5-8s after nav before eval
• performance.getEntriesByType has a 150-entry default buffer — large pages may truncate

Tabs

$B tabs                              # List all tabs
$B tabs new https://google.com       # New tab with URL
$B tabs activate <id>                # Switch to tab
$B tabs close <id>                   # Close tab
$B tabs info <id>                    # Tab details
$B tabs stop <id>                    # Stop loading

Browser Events

ABP surfaces events that normally require polling — dialogs, file pickers, downloads, select dropdowns, permission prompts. They appear in the output of any action.

# Dialogs (alert, confirm, prompt)
$B dialog                            # Check for pending dialog
$B dialog accept                     # Accept
$B dialog accept "response text"     # Accept prompt with text
$B dialog dismiss                    # Dismiss/cancel

# Downloads
$B download                          # List all
$B download list --state completed   # Filter by state
$B download list --limit 5           # Limit results
$B download status <id>              # Check progress
$B download cancel <id>              # Cancel
$B download get <id>                 # Get content (base64)
$B download get <id> --max-size 1048576  # Limit content size

# File chooser (triggered by file input click)
$B file <chooser_id> /path/to/file.pdf       # Upload file
$B file <chooser_id> file1.jpg file2.jpg     # Multiple files
$B file <chooser_id> --cancel                # Cancel picker
$B file <chooser_id> --save /path/out.pdf    # Save dialog

# Native <select> dropdown
$B select <select_id> 2              # Choose option at index

# Permissions (geolocation, camera, etc.)
$B permission                         # List pending
$B permission grant <id>              # Grant
$B permission grant <id> --lat 42.36 --lng -71.06  # Grant geo with coords
$B permission deny <id>               # Deny

Event Indicators

When events occur during any action, they're printed automatically:

  → https://new-page.com              # Navigation happened
  ⚠ dialog (confirm): Delete item?    # Dialog appeared
  📁 file chooser id=fc_1             # File picker opened
  ⬇ download: report.pdf              # Download started
  ▾ select id=s_1 (5 options)         # Native select opened
  🔐 permission id=p_1 geolocation    # Permission requested
  ↗ popup: https://popup.com          # Popup window

Execution Control

ABP freezes JS between actions by default. You can control this:

$B execution                          # Current state
$B execution pause                    # Freeze JS & virtual time
$B execution resume                   # Unfreeze

Session & History

# Session info
$B session-data                       # Session directory & database paths
$B status                             # Browser readiness

# History (SQLite-backed)
$B history                            # List sessions
$B history current                    # Current session
$B history session <id>               # Session details
$B history export <id>                # Export full session data
$B history actions                    # Action log
$B history action <id>                # Single action detail
$B history events                     # Browser events log
$B history event <id>                 # Single event detail
$B history clear                      # Delete all

# Debug server (separate tool)
npx abp-debug                        # Web UI on :8223 — action timeline, screenshots, live updates

Advanced

# Batch: multiple actions, one screenshot
$B batch '[{"type":"mouse_click","x":350,"y":200},{"type":"keyboard_type","text":"hello"},{"type":"keyboard_press","key":"ENTER"}]'

# Lifecycle
$B shutdown                           # Graceful shutdown
$B shutdown --timeout 10000           # Custom timeout

Global Flags

Speed Rules

Token Cost Per Command

What To Use When (Decision Tree)

"Am I on the right page?"     → eval 'location.href'  or  eval 'document.title'
"What can I interact with?"   → observe
"Did my action work?"         → eval (check DOM/URL state)  or  assert
"What data is on the page?"   → text  or  eval
"What does it look like?"     → screenshot
"I'm lost / complex layout"   → screenshot
"Waiting for async result"    → watch --text "..." --timeout 30000

Default to eval/text/observe. Escalate to screenshot only when layout matters.

Observe — Structured Page Snapshot (~150 tokens)

Use observe instead of screenshot when you need to know what's on the page but don't need to see it:

$B observe               # → url, title, headings, inputs, buttons, errors
$B observe "form"        # Scoped to a CSS selector (~50 tokens)
$B observe ".modal"      # Just the modal content
$B observe --shot        # Structured data + screenshot in one call
$B observe --json        # Raw JSON output

Returns: URL, title, visible interactive elements (inputs with names/values/placeholders, buttons with text/hrefs), headings, and error messages. Only visible elements — hidden inputs and off-screen elements are filtered out. Enough to decide next action without vision.

Assert — Pass/Fail Verification (~20 tokens)

After actions, verify without vision:

$B assert text "Welcome back"        # Page contains text?
$B assert selector "#dashboard"      # Element exists?
$B assert url "/dashboard"           # URL contains string?
$B assert title "Dashboard"          # Title matches?

Returns ✓ PASS or ✗ FAIL: <context>. Zero tokens on happy path.

Watch — Wait For Async UI (~20 tokens)

Don't write polling loops. One command, one result:

$B watch --text "Payment complete" --timeout 30000
$B watch --selector ".loaded" --timeout 5000
$B watch --url "/success" --timeout 10000
$B watch --eval "document.querySelectorAll('.item').length >= 10" --timeout 5000

Resumes JS, polls internally, returns when matched or timed out.

Core Speed Rules

1. Start ABP first: browser.js start
2. Don't screenshot every step: Only screenshot when you need to see layout/visuals.
3. Use observe as default awareness: After nav or complex actions, observe gives page state in ~150 tokens vs ~1500 for a screenshot.
4. Use assert for verification: After form submission, assert text "Success" — not screenshot + read.
5. Observe the URL after search: Most SPAs encode filters in URL params. Copy it, modify it, nav directly next time.
6. Extract data via eval, not vision: One JS query extracts 10 results faster than scrolling + screenshotting.
7. Batch related inputs: Click + type + Enter = one batch call instead of three.
8. Use text for simple data: text is faster than eval for plain text extraction.
9. Use watch instead of polling loops: When waiting for loading/async results.
10. Use network for slow pages: After nav to an SPA, network waits for all pending XHR/fetch to complete.
11. Use pick for ambiguity: When coordinates are unclear, let the user click.

Anti-Pattern

click → screenshot → read image → decide → click → screenshot → ...
(each step: ~3s for screenshot + LLM vision round-trip)

Fast Patterns

Blind execution (known flow):

$B nav https://app.com
$B click 450 300          # login button
$B type user@example.com
$B key TAB
$B type mysecretpassword
$B key ENTER
$B assert text "Dashboard"   # verify once at the end

Explore then act (unknown page):

$B nav https://app.com
$B observe                # structured snapshot, 150 tokens
# Now you know what's on the page — act on it
$B click 450 300
$B assert url "/profile"

Data extraction (scraping):

$B nav https://shop.com/products
$B eval '([...document.querySelectorAll(".product")].map(e => ({name: e.querySelector("h2").textContent, price: e.querySelector(".price").textContent})))'
# One call, all data. No scrolling, no screenshots.

Multi-page parallel (compare/verify across pages):

$B nav https://app.com/page1 --new    # tab 1
$B nav https://app.com/page2 --new    # tab 2
$B nav https://app.com/page3 --new    # tab 3
# Work each tab independently via --tab <id>
# Merge results at the end

Async wait (payment, loading):

$B click 500 400                           # submit payment
$B watch --text "Payment confirmed" --timeout 30000   # wait, don't poll
$B screenshot                              # visual confirmation