red-green

1// red-green: run the tests after any turn that edited files.
2//
3//   /red-green npm test       set the test command for this project
4//   /red-green detect         pick one from package.json, pyproject.toml, Makefile, Cargo.toml, or go.mod
5//   /red-green                show the command and the last result
6//   /red-green off | on       pause or resume
7//   /fix                      send the last failure to Claude and ask it to fix it
8//
9// After a turn in which Claude edited a file, the command runs and a line under
10// the answer says pass or fail. Nothing runs when nothing was edited.
11
12const TIMEOUT_MS = 180_000
13const TAIL_LINES = 30
14
15type Settings = { command: string; enabled: boolean }
16type Result = { command: string; exitCode: number; ms: number; tail: string; at: number }
17
18let root = ''
19let settings: Settings = { command: '', enabled: true }
20let dirty = false
21let running = false
22let last: Result | null = null
23// Files Claude edited this turn, to notice when it changed what the test command runs.
24let edited = new Set<string>()
25
26// Files that define what a test command does. An edit to one of these this turn
27// means running the command would execute code Claude just wrote, without a
28// permission prompt, so the user is asked first.
29const DEFINES_TESTS = /(?:^|\/)(?:package\.json|Makefile|GNUmakefile|pyproject\.toml|setup\.cfg|setup\.py|conftest\.py|pytest\.ini|tox\.ini|Cargo\.toml|build\.rs|go\.mod|Rakefile|Gemfile|build\.gradle(?:\.kts)?|pom\.xml|\.mocharc[^/]*|(?:jest|vitest|karma|playwright|cypress|ava)\.config\.[^/]+|\.npmrc|\.yarnrc[^/]*)$/
30
31function changedTestDefinition(): string[] {
32  const named = settings.command.split(/\s+/).filter((w) => /[./]/.test(w) && !w.startsWith('-'))
33  return [...edited].filter((f) => DEFINES_TESTS.test(f) || named.some((n) => f === n || f.endsWith('/' + n)))
34}
35
36async function load($) {
37  try {
38    root = await $.session.root()
39    const saved = await $.store.get('red-green:' + root)
40    if (saved && typeof saved === 'object') settings = { command: String(saved.command ?? ''), enabled: saved.enabled !== false }
41  } catch {
42    settings = { command: '', enabled: true }
43  }
44}
45
46async function save($) {
47  await $.store.set('red-green:' + root, settings)
48}
49
50async function detect($): Promise<string | null> {
51  const has = async (file: string) => {
52    try {
53      return await $.fs.exists(root + '/' + file)
54    } catch {
55      return false
56    }
57  }
58  if (await has('package.json')) {
59    try {
60      const pkg = JSON.parse(await $.fs.read(root + '/package.json'))
61      if (pkg.scripts && pkg.scripts.test) return (await has('pnpm-lock.yaml')) ? 'pnpm test' : (await has('yarn.lock')) ? 'yarn test' : 'npm test'
62    } catch {
63      // Unreadable package.json: keep looking.
64    }
65  }
66  if (await has('pyproject.toml')) return 'pytest'
67  if (await has('Cargo.toml')) return 'cargo test'
68  if (await has('go.mod')) return 'go test ./...'
69  if (await has('Makefile')) {
70    try {
71      if (/^test:/m.test(await $.fs.read(root + '/Makefile'))) return 'make test'
72    } catch {
73      // Unreadable Makefile.
74    }
75  }
76  return null
77}
78
79function tail(text: string): string {
80  const lines = text.split('\n').filter((l) => l.trim())
81  return lines.slice(-TAIL_LINES).join('\n')
82}
83
84async function run($): Promise<Result> {
85  const started = Date.now()
86  try {
87    const r = await $.process.run(['sh', '-c', settings.command], { cwd: root, timeoutMs: TIMEOUT_MS })
88    return { command: settings.command, exitCode: r.exitCode, ms: Date.now() - started, tail: tail(r.stdout + '\n' + r.stderr), at: started }
89  } catch (error) {
90    return { command: settings.command, exitCode: -1, ms: Date.now() - started, tail: String(error), at: started }
91  }
92}
93
94function verdict(r: Result): string {
95  const secs = (r.ms / 1000).toFixed(1) + 's'
96  if (r.exitCode === 0) return 'red-green: tests passed (' + r.command + ', ' + secs + ')'
97  if (r.exitCode === -1) return 'red-green: could not run ' + r.command + ' (' + r.tail.slice(0, 120) + ')'
98  return 'red-green: tests FAILED, exit ' + r.exitCode + ' (' + r.command + ', ' + secs + '). /fix sends the failure to Claude.'
99}
100
101export function register(on) {
102  on('session.start', async ($, e, next) => {
103    await load($)
104    for (const c of [
105      { name: 'red-green', description: 'Set or show the test command that runs after edits', argumentHint: '[<command> | detect | on | off]' },
106      { name: 'fix', description: 'Ask Claude to fix the last failing test run' },
107    ]) {
108      try {
109        await $.command.register(c)
110      } catch (error) {
111        $.ui.log('could not register /' + c.name + ': ' + error)
112      }
113    }
114    return next(e)
115  })
116
117  on('command.run', { command: 'red-green' }, async ($, e) => {
118    const args = e.args.trim()
119    if (args === 'on' || args === 'off') {
120      settings.enabled = args === 'on'
121      await save($)
122      return { text: settings.enabled ? 'red-green on.' : 'red-green off. Tests are not run after edits.' }
123    }
124    if (args === 'detect') {
125      const found = await detect($)
126      if (!found) return { text: 'Nothing recognized. Set one with /red-green <command>.' }
127      settings.command = found
128      await save($)
129      return { text: 'Test command for this project: ' + found }
130    }
131    if (args) {
132      settings.command = args
133      await save($)
134      return { text: 'Test command for this project: ' + args }
135    }
136    return {
137      text: (settings.command ? 'Test command: ' + settings.command : 'No test command. /red-green detect or /red-green <command>.') +
138        (settings.enabled ? '' : ' (off)') + (last ? '\nLast run: ' + verdict(last) : ''),
139    }
140  }).catch(async () => ({ text: 'red-green: the command failed, so nothing changed.' }))
141
142  on('command.run', { command: 'fix' }, async ($) => {
143    if (!last || last.exitCode === 0) return { text: 'No failing test run to fix.' }
144    const failure = last
145    // A prompt can't be submitted from inside a command, which holds the turn it
146    // would wait on. A zero-delay timer runs outside the command and submits it.
147    $.clock.after(0, async () => {
148      try {
149        await $.prompt.submit({
150          text: 'The test command `' + failure.command + '` failed with exit code ' + failure.exitCode + ' after your last changes. The end of its output:\n\n```\n' + failure.tail + '\n```\n\nFix the failures, then run the tests again.',
151        })
152      } catch (error) {
153        $.ui.log('red-green could not send the failure to Claude: ' + error)
154      }
155    })
156    return { text: 'Sending the failure to Claude.' }
157  }).catch(async () => ({ text: 'red-green: could not send the failure to Claude.' }))
158
159  on('tool.call', { tool: ['Edit', 'Write', 'MultiEdit', 'NotebookEdit'] }, async ($, e, next) => {
160    const result = await next(e)
161    if (typeof e.agentId !== 'string' && !result.deny && !result.isError) {
162      dirty = true
163      const file = e.tool === 'NotebookEdit' ? e.notebook_path : e.file_path
164      if (typeof file === 'string') edited.add(root && file.startsWith(root + '/') ? file.slice(root.length + 1) : file)
165    }
166    return result
167  }).catch(async ($, e, next) => next(e))
168
169  on('turn.complete', async ($, e, next) => {
170    if (typeof e.agentId === 'string' || e.isAborted || !dirty || !settings.enabled || !settings.command || running) return next(e)
171    dirty = false
172    const risky = changedTestDefinition()
173    edited = new Set()
174    if (risky.length) {
175      let answer = 'Skip'
176      try {
177        answer = await $.ui.ask('red-green: Claude changed ' + risky.join(', ') + ' this turn, which can change what `' + settings.command + '` runs. Run it anyway?', ['Skip', 'Run'])
178      } catch {
179        // Nobody to ask: skip.
180      }
181      if (answer !== 'Run') return { text: 'red-green: skipped ' + settings.command + ' because Claude changed ' + risky.join(', ') + ' this turn. Review it, then run the tests yourself or ask Claude to.' }
182    }
183    running = true
184    try {
185      last = await run($)
186    } finally {
187      running = false
188    }
189    return { text: verdict(last) }
190  }).catch(async ($, e, next) => next(e))
191}
192