dsh-facet/test/scope.test.js

import assert from 'node:assert/strict'
import { test } from 'node:test'

import {
  displayPath,
  facetContextText,
  facetRuleText,
  isWideningCall,
  outsideReason,
  pathArgumentsFor,
  widenReason,
} from '../lib/scope.js'

test('pathArgumentsFor reads the path argument of every guarded tool', () => {
  assert.deepEqual(pathArgumentsFor('read', { file_path: 'src/a.ts' }), ['src/a.ts'])
  assert.deepEqual(pathArgumentsFor('write', { file_path: 'src/a.ts', content: 'x' }), ['src/a.ts'])
  assert.deepEqual(pathArgumentsFor('edit', { file_path: 'src/a.ts' }), ['src/a.ts'])
  assert.deepEqual(pathArgumentsFor('read_image', { file_path: 'a.png' }), ['a.png'])
  assert.deepEqual(pathArgumentsFor('grep', { pattern: 'x', path: 'src' }), ['src'])
  assert.deepEqual(pathArgumentsFor('glob', { pattern: '*.ts', path: 'src' }), ['src'])
  assert.deepEqual(pathArgumentsFor('str_replace_editor', { path: 'src/a.ts' }), ['src/a.ts'])
  assert.deepEqual(pathArgumentsFor('recall', { path: 'src', focus: 'src/controllers' }), [
    'src',
    'src/controllers',
  ])
})

test('pathArgumentsFor has no opinion where it cannot have one', () => {
  // The deliberate hole: a shell command cannot be judged from argv.
  assert.deepEqual(pathArgumentsFor('bash', { command: 'cat /etc/passwd' }), [])
  // Unknown tools are not guessed at.
  assert.deepEqual(pathArgumentsFor('mcp_something', { path: '/etc' }), [])
  // An omitted path means the session directory, which is already in scope.
  assert.deepEqual(pathArgumentsFor('grep', { pattern: 'x' }), [])
  // Unvalidated JSON must never make the guard throw.
  assert.deepEqual(pathArgumentsFor('read', null), [])
  assert.deepEqual(pathArgumentsFor('read', 'nonsense'), [])
  assert.deepEqual(pathArgumentsFor('read', { file_path: 42 }), [])
  assert.deepEqual(pathArgumentsFor('read', { file_path: '   ' }), [])
  assert.deepEqual(pathArgumentsFor('grep', { path: { nested: '/etc' } }), [])
})

test('isWideningCall is true only for the one act that needs the user', () => {
  assert.equal(isWideningCall('facet', { action: 'add', paths: ['x'] }), true)
  // Narrowing and reading cannot show the agent anything new.
  assert.equal(isWideningCall('facet', { action: 'remove', paths: ['x'] }), false)
  assert.equal(isWideningCall('facet', { action: 'reset' }), false)
  assert.equal(isWideningCall('facet', { action: 'status' }), false)
  assert.equal(isWideningCall('read', { action: 'add' }), false)
  assert.equal(isWideningCall('facet', null), false)
})

test('facetRuleText states the rule and never the binding', () => {
  const rule = facetRuleText()

  // Mode-neutral by construction. A prompt section is registered once as a plain
  // string, and a `volatile()` edit updates the config reference without
  // re-applying the plugin — so a `mode` interpolated here would freeze at load
  // while the guard went on enforcing the new one. The mode-specific sentence
  // lives in the binding, which is a callback.
  assert.match(rule, /Work inside the facet\./)
  assert.doesNotMatch(rule, /refused|put to the user as a question/)
  assert.match(rule, /Never widen the scope on your own initiative/)

  // The rule must not name a path: a changing system prompt invalidates the
  // prompt cache for the whole conversation.
  assert.doesNotMatch(rule, /\/|src\//)

  assert.equal(facetContextText({ cwd: '/a', root: '/a/b', extras: [], mode: 'off' }), '')
})

test('facetContextText carries the binding that does change', () => {
  const ask = facetContextText({ cwd: '/w', root: '/w/src/room', extras: [], mode: 'ask' })
  assert.equal(
    ask,
    'facet: /w/src/room\n' +
      'outside the facet: put to the user as a question — say in one line what you need and why, then record it with `facet action=add` so the rest of the session does not have to ask again',
  )

  const deny = facetContextText({ cwd: '/w', root: '/w/src/room', extras: ['/w/src/shared'], mode: 'deny' })
  assert.equal(
    deny,
    'facet: /w/src/room\n' +
      'granted outside it: src/shared\n' +
      'outside the facet: refused — `facet action=add` asks the user to grant a path, and is the only way to widen the scope',
  )

  // The binding is the only half that can follow a live edit, so the two modes
  // have to read differently here — they no longer differ in the rule.
  assert.notEqual(ask, deny)

  // Unscoped sessions contribute nothing rather than an empty heading.
  assert.equal(facetContextText({ cwd: '/w', root: undefined, extras: [], mode: 'ask' }), '')
  assert.equal(facetContextText({ cwd: '/w', root: '/w/src/room', extras: [], mode: 'off' }), '')
})

test('displayPath prefers the shortest unambiguous form', () => {
  assert.equal(displayPath('/w', '/w/src/a.ts'), 'src/a.ts')
  assert.equal(displayPath('/w', '/w'), '.')
  assert.equal(displayPath('/w', '/other/a.ts'), '/other/a.ts')
  assert.equal(displayPath('', '/w/a.ts'), '/w/a.ts')
})

test('outsideReason names the path, the boundary and the way forward', () => {
  const reason = outsideReason({
    cwd: '/w/src/controllers/room',
    path: '/w/src/shared/types.ts',
    root: '/w/src/controllers/room',
    mode: 'ask',
  })
  assert.match(reason, /src\/shared\/types\.ts/)
  assert.match(reason, /src\/controllers\/room/)
  // A denial that does not say how to proceed is one the agent routes around.
  assert.match(reason, /facet action=add/)
})

test('widenReason survives an add with no usable paths', () => {
  assert.match(widenReason(['src/shared']), /src\/shared/)
  assert.match(widenReason([]), /nothing/)
})