edwinhu/dev-test-hammerspoon

Announce: "I'm using dev-test-hammerspoon for macOS desktop automation."

<EXTREMELY-IMPORTANT> ## Gate Reminder

Before taking screenshots or running E2E tests, you MUST complete all 6 gates from dev-tdd:

GATE 1: BUILD
GATE 2: LAUNCH (with file-based logging)
GATE 3: WAIT
GATE 4: CHECK PROCESS
GATE 5: READ LOGS ← MANDATORY, CANNOT SKIP
GATE 6: VERIFY LOGS
THEN: E2E tests/screenshots

You loaded dev-tdd earlier. Follow the gates now. </EXTREMELY-IMPORTANT>

Contents

• Tool Availability Gate
• When to Use Hammerspoon
• Hammerspoon Setup
• Input Simulation
• Application Control
• Window Management
• Screenshots
• Complete E2E Example
• Alternative: cliclick

macOS Desktop Automation

<EXTREMELY-IMPORTANT> ## Tool Availability Gate

Verify Hammerspoon is installed before proceeding.

# Check Hammerspoon installation (both CLI and app)
which hs || echo "MISSING: hs CLI"
ls /Applications/Hammerspoon.app 2>/dev/null || echo "MISSING: Hammerspoon.app"

If missing:

STOP: Cannot proceed with macOS automation.

Missing tool: Hammerspoon (required for macOS E2E testing)

Install with:
  # Install via nix-darwin, or verify: hammerspoon -c "print('ok')"

After installing:
  1. Open Hammerspoon.app
  2. Grant Accessibility permissions in System Preferences
  3. In Hammerspoon console, run: hs.ipc.cliInstall()
  4. Add to ~/.hammerspoon/init.lua: require("hs.ipc")

Reply when installed and I'll continue testing.

This gate is non-negotiable. Missing tools = full stop. </EXTREMELY-IMPORTANT>

<EXTREMELY-IMPORTANT> ## When to Use Hammerspoon

Use Hammerspoon for:

• macOS native application automation
• System-wide keyboard shortcuts
• Window management and positioning
• Menu item automation
• Clipboard verification
• Multi-app workflows on macOS

Do not use Hammerspoon for:

• Testing web applications (use Chrome MCP or Playwright)
• Cross-platform testing needed
• Linux desktop automation (use dev-test-linux)

For web testing, discover and read the relevant skill: Related skills:

• Read ${CLAUDE_SKILL_DIR}/../../skills/dev-test-chrome/SKILL.md and follow its instructions.
• Read ${CLAUDE_SKILL_DIR}/../../skills/dev-test-playwright/SKILL.md and follow its instructions.
• Chrome MCP skill - debugging
• Playwright skill - CI/CD

Hammerspoon Facts

• Hammerspoon is more reliable than AppleScript for macOS automation, and web-testing tools (Chrome MCP, Playwright) cannot drive native macOS apps at all — substituting either leaves the native UI untested.
• Accessibility permissions are a one-time setup; avoiding the setup by testing manually produces no automated evidence, so "it worked" is an unverified claim. </EXTREMELY-IMPORTANT>

Hammerspoon Setup

One-time setup in ~/.hammerspoon/init.lua:

require("hs.ipc")  -- Enables CLI

Reload config after changes:

hs -c 'hs.reload()'  # Reload Hammerspoon configuration

Input Simulation

hs.eventtap - Keyboard/Mouse

-- Type text (simulates keystrokes)
hs.eventtap.keyStrokes("hello world")

-- Key press with modifiers
hs.eventtap.keyStroke({"cmd"}, "c")           -- Cmd+C
hs.eventtap.keyStroke({"cmd", "shift"}, "s")  -- Cmd+Shift+S
hs.eventtap.keyStroke({"ctrl", "alt"}, "t")   -- Ctrl+Alt+T
hs.eventtap.keyStroke({}, "return")           -- Enter key
hs.eventtap.keyStroke({}, "escape")           -- Escape key

-- Function keys
hs.eventtap.keyStroke({}, "f1")
hs.eventtap.keyStroke({"cmd"}, "f5")

-- Mouse clicks
hs.eventtap.leftClick({x=100, y=200})
hs.eventtap.rightClick({x=100, y=200})
hs.eventtap.middleClick({x=100, y=200})
hs.eventtap.doubleClick({x=100, y=200})

-- Mouse movement
hs.mouse.absolutePosition({x=500, y=300})

-- Scroll
hs.eventtap.scrollWheel({0, -5}, {})  -- Scroll down
hs.eventtap.scrollWheel({0, 5}, {})   -- Scroll up

Running from CLI

# Execute Lua code directly
hs -c 'hs.eventtap.keyStroke({"cmd"}, "c")'  # Run inline Lua code via CLI

# Execute a script file
hs /path/to/test_script.lua  # Run Hammerspoon script from file

# Pipe script via stdin
echo 'hs.eventtap.keyStrokes("test")' | hs -s  # Run script piped through stdin

Application Control

hs.application

-- Launch or focus app by name
local app = hs.application.launchOrFocus("Safari")

-- Launch app by bundle ID
hs.application.launchOrFocusByBundleID("com.apple.Safari")

-- Get running app
local app = hs.application.get("Safari")
if app then
    app:activate()       -- Bring to front
    app:hide()           -- Hide
    app:unhide()         -- Unhide
    app:kill()           -- Terminate gracefully
    app:kill9()          -- Force kill
end

-- Get frontmost app
local front = hs.application.frontmostApplication()
print(front:name())
print(front:bundleID())

-- List all running apps
for _, app in ipairs(hs.application.runningApplications()) do
    print(app:name())
end

-- Wait for app to launch
hs.timer.waitUntil(
    function() return hs.application.get("MyApp") ~= nil end,
    function() print("App launched") end,
    0.5  -- Check every 0.5 seconds
)

Menu Items

-- Click menu item
local app = hs.application.get("Safari")
app:selectMenuItem({"File", "New Window"})
app:selectMenuItem({"Edit", "Paste"})

-- Check if menu item exists
local menuItem = app:findMenuItem({"File", "Save"})
if menuItem then
    print("Save is available, enabled:", menuItem.enabled)
end

Window Management

hs.window

-- Get focused window
local win = hs.window.focusedWindow()
print(win:title())
print(win:frame())  -- {x, y, w, h}

-- Get app's windows
local app = hs.application.get("Safari")
local wins = app:allWindows()
for _, win in ipairs(wins) do
    print(win:title())
end

-- Get window by title (partial match)
local win = hs.window.get("My Document")

-- Window actions
win:focus()           -- Focus window
win:maximize()        -- Maximize
win:minimize()        -- Minimize to dock
win:close()           -- Close window

-- Move/resize
win:setFrame({x=100, y=100, w=800, h=600})
win:move({100, 0})    -- Move relative
win:setSize({800, 600})
win:centerOnScreen()

-- Get window position and size
local frame = win:frame()
print("Position:", frame.x, frame.y)
print("Size:", frame.w, frame.h)

Screenshots

<EXTREMELY-IMPORTANT> ### The Iron Law of Visual Verification

Every E2E test MUST include screenshot evidence.

After completing a workflow, capture a screenshot to prove success. </EXTREMELY-IMPORTANT>

screencapture (CLI)

# Full screen (all displays)
screencapture /tmp/screenshot.png  # Capture entire screen to file

# Main screen only
screencapture -m /tmp/main_screen.png  # Capture primary screen only

# Specific window (interactive - click to select)
screencapture -w /tmp/window.png  # Interactively select window to capture

# Specific region
screencapture -R 100,200,800,600 /tmp/region.png  # Capture rectangular region (x,y,w,h)

# Without window shadow
screencapture -o /tmp/no_shadow.png  # Capture without window shadows

# Silent (no camera sound)
screencapture -x /tmp/silent.png  # Capture silently without shutter sound

# To clipboard instead of file
screencapture -c  # Capture to clipboard

# Combined: silent, no shadow, specific region
screencapture -x -o -R 0,0,1920,1080 /tmp/clean.png  # Capture region silently without shadows

hs.screen (Hammerspoon)

-- Capture focused window
local win = hs.window.focusedWindow()
if win then
    local img = win:snapshot()
    img:saveToFile("/tmp/window.png")
end

-- Capture entire screen
local screen = hs.screen.mainScreen()
local img = screen:snapshot()
img:saveToFile("/tmp/screen.png")

-- Capture specific region
local img = hs.screen.mainScreen():snapshot({x=0, y=0, w=800, h=600})
img:saveToFile("/tmp/region.png")

Complete E2E Example

<EXTREMELY-IMPORTANT> ### E2E Test Structure

Every Hammerspoon E2E test MUST:

1. Launch - Start the application
2. Verify launch - Assert app is running
3. Interact - Perform user actions
4. Verify state - Check expected state (clipboard, window, etc.)
5. Screenshot - Capture visual evidence
6. Cleanup - Close app, restore state </EXTREMELY-IMPORTANT>

-- test_workflow.lua
-- Run with: hs /path/to/test_workflow.lua

local function test_app_workflow()
    -- 1. Launch app
    print("Launching app...")
    hs.application.launchOrFocus("TextEdit")
    hs.timer.usleep(1000000)  -- Wait 1 second

    -- 2. Verify app launched
    local app = hs.application.get("TextEdit")
    assert(app, "FAIL: TextEdit did not launch")
    print("App launched: " .. app:name())

    -- 3. Create new document
    hs.eventtap.keyStroke({"cmd"}, "n")
    hs.timer.usleep(500000)

    -- 4. Type content
    hs.eventtap.keyStrokes("Hello, this is an automated test!")
    hs.timer.usleep(300000)

    -- 5. Select all and copy
    hs.eventtap.keyStroke({"cmd"}, "a")
    hs.timer.usleep(100000)
    hs.eventtap.keyStroke({"cmd"}, "c")

    -- 6. Verify clipboard
    local clipboard = hs.pasteboard.getContents()
    assert(clipboard:find("automated test"), "FAIL: Clipboard doesn't match")
    print("Clipboard verified: " .. clipboard)

    -- 7. Take screenshot
    local win = hs.window.focusedWindow()
    local img = win:snapshot()
    img:saveToFile("/tmp/test_result.png")
    print("Screenshot saved to /tmp/test_result.png")

    -- 8. Close without saving
    hs.eventtap.keyStroke({"cmd"}, "w")
    hs.timer.usleep(500000)
    hs.eventtap.keyStroke({}, "d")  -- "Don't Save" button

    print("PASS: Workflow completed successfully")
end

-- Run the test
local status, err = pcall(test_app_workflow)
if not status then
    print("FAIL: " .. tostring(err))
    os.exit(1)
end
os.exit(0)

Run from CLI:

hs /path/to/test_workflow.lua && echo "TEST PASSED" || echo "TEST FAILED"  # Execute test script and report result

Alternative: cliclick

For simpler needs, cliclick provides CLI-based mouse/keyboard control:

# Install cliclick tool
# Install cliclick via nix-darwin, or verify: cliclick -V

# Mouse click at coordinates
cliclick c:100,200       # Left-click at coordinates
cliclick rc:100,200      # Right-click at coordinates
cliclick dc:100,200      # Double-click at coordinates

# Move mouse
cliclick m:500,300  # Move mouse to coordinates

# Type text
cliclick t:"Hello world"  # Type text at current cursor position

# Key press
cliclick kp:return  # Press return key
cliclick kp:escape  # Press escape key
cliclick kd:cmd kp:c ku:cmd  # Press Cmd+C (key down, press, key up)

# Wait (milliseconds)
cliclick w:500  # Wait for 500 milliseconds

cliclick is useful for simple scripts but lacks app control - prefer Hammerspoon for complex E2E tests.

Output Requirements

Every test run MUST be documented in LEARNINGS.md:

## macOS E2E Test: [Description]

**Tool:** Hammerspoon

**Script:**
```bash
hs /path/to/test_script.lua

Output:

Launching app...
App launched: TextEdit
Clipboard verified: Hello, this is an automated test!
Screenshot saved to /tmp/test_result.png
PASS: Workflow completed successfully

Result: PASS

Screenshot: /tmp/test_result.png

## Integration

This skill is referenced by `dev-test` for macOS desktop automation.

Read `${CLAUDE_SKILL_DIR}/../../skills/dev-tdd/SKILL.md` and follow its instructions.