// own-tree.mjs — Fixtures that ARE the process's own working tree (S3c).
//
// .llm-security/policy.json is honored for an explicit scan root only when
// that root is the caller's own working tree: under process.cwd(), never
// under os.tmpdir() (scanners/lib/own-working-tree.mjs). Tests of LOCAL
// policy behaviour therefore need a fixture that is the caller's own tree —
// a throwaway dir outside os.tmpdir() and outside this repo's git tree
// (under $HOME, same placement rule as ignore-file-scope.test.mjs), made the
// process cwd while the test runs. node --test runs each file in its own
// process, so the chdir never leaks into another test file.

import { mkdtempSync } from 'node:fs';
import { join } from 'node:path';
import { homedir } from 'node:os';

/** Create a throwaway own-tree fixture dir (caller removes it). */
export function mkOwnTreeDir(prefix) {
  return mkdtempSync(join(homedir(), `.${prefix}`));
}

/** Run fn with dir as the process cwd; the previous cwd is always restored. */
export async function inOwnTree(dir, fn) {
  const prev = process.cwd();
  process.chdir(dir);
  try {
    return await fn();
  } finally {
    process.chdir(prev);
  }
}