TUI Testing Skill

This skill guides you through testing terminal user interfaces using tuivision's MCP tools.

When to Use

• Testing a TUI application (htop, vim, custom ncurses apps)
• Validating terminal output and layout
• Automating interactive CLI workflows
• Visual regression testing for terminal apps
• Debugging terminal rendering issues

Available Tools

The tuivision MCP server provides these tools:

Tool	Purpose
spawn_tui	Start a TUI app in a virtual terminal
send_input	Send keystrokes (text, arrows, ctrl+c, etc.)
get_screen	Get terminal state as text or structured data
get_screenshot	Render terminal to PNG or SVG image
resize_session	Change terminal dimensions
list_sessions	Show all active sessions
close_session	Clean up a session

Workflow

1. Spawn the Application

spawn_tui command="htop" cols=120 rows=40

Returns a session_id for subsequent operations.

For Bubble Tea / Charm apps (Go TUI frameworks), add TTY compatibility flags:

spawn_tui command="./my-bubbletea-app" cols=120 rows=40 use_script=true answer_queries=true

• use_script: Wraps in script command for /dev/tty access
• answer_queries: Auto-responds to ANSI terminal queries

2. Wait for Startup

After spawning, give the app time to initialize:

• Simple apps: immediate
• Complex apps (htop, vim): 100-500ms delay before reading screen

3. Interact

Send input using send_input:

# Type text
send_input session_id="..." input="hello world"

# Special keys
send_input session_id="..." key="enter"
send_input session_id="..." key="ctrl+c"
send_input session_id="..." key="up"

# Sequence of keys
send_input session_id="..." keys=["tab", "tab", "enter"]

Special keys supported:

• Navigation: up, down, left, right, home, end, pageup, pagedown
• Editing: enter, tab, backspace, delete, escape
• Control: ctrl+c, ctrl+d, ctrl+z, ctrl+l
• Function: f1 through f12

4. Observe State

Get terminal content:

# Quick text view
get_screen session_id="..." format="text"

# With cursor position
get_screen session_id="..." format="compact"

# Full cell data (colors, attributes)
get_screen session_id="..." format="full"

5. Visual Verification

Take screenshots for visual inspection:

# PNG screenshot (returned as base64 image)
get_screenshot session_id="..." format="png"

# SVG for scalable output
get_screenshot session_id="..." format="svg" font_size=16

6. Clean Up

Always close sessions when done:

close_session session_id="..."

Testing Patterns

Assert Text Content

1. get_screen with format="text"
2. Check for expected strings in output
3. Verify cursor position if needed

Visual Regression

1. Take screenshot of known-good state
2. After changes, take new screenshot
3. Compare visually or with diff tools

Interactive Flow Testing

1. Spawn app
2. Send navigation/input sequence
3. Verify each intermediate state
4. Validate final state

Error Handling

• Always wrap in try/catch
• Close sessions on failure
• Check for app crash via get_screen returning empty/error

Tips

• Timing: TUI apps need time to render. Add small delays between input and screen reads.
• Terminal size: Match real-world dimensions (80x24 is standard, 120x40 for wider apps).
• Colors: Use get_screen format="full" to verify color/attribute rendering.
• Exit cleanly: Send ctrl+c or q before close_session for graceful app shutdown.
• Bubble Tea / Charm: Always use use_script=true and answer_queries=true for Go TUI apps.
• Blank screen? If app shows blank, it likely needs the TTY flags above.

Example: Test htop

1. spawn_tui command="htop" cols=120 rows=40
2. [wait 200ms]
3. get_screenshot session_id="..." format="png"
4. send_input session_id="..." key="q"
5. close_session session_id="..."

Example: Test vim

1. spawn_tui command="vim test.txt" cols=80 rows=24
2. send_input session_id="..." key="i"  # insert mode
3. send_input session_id="..." input="Hello, World!"
4. send_input session_id="..." key="escape"
5. get_screen session_id="..." format="text"
6. send_input session_id="..." keys=[":","q","!","enter"]
7. close_session session_id="..."

Example: Test Bubble Tea App

Bubble Tea apps (Go) require TTY compatibility flags:

1. spawn_tui command="./my-bubbletea-app" cols=80 rows=24 use_script=true answer_queries=true
2. [wait 500ms for app to initialize]
3. get_screenshot session_id="..." format="png"
4. send_input session_id="..." key="down"
5. get_screen session_id="..." format="text"
6. send_input session_id="..." key="q"
7. close_session session_id="..."

Why these flags? Bubble Tea queries terminal capabilities (cursor position, colors) before rendering. Without responses, the app hangs waiting. use_script provides /dev/tty access, and answer_queries auto-responds to ANSI queries.