test(ci): give policy.json ci.failOn / ci.compact a real test

The "--fail-on via policy.json" block wrote a policy.json into a tmp root it
never scanned and passed --fail-on on the CLI, so ci.failOn / ci.compact had
no test at all. The rewrite scans a copy of grade-a-project as the process's
own working tree (the only place policy.json is honored since v8.1.0):
WARNING with 0 critical exits 1 by default, and exits 0 only if
`ci.failOn: 'critical'` is read from the policy. Measured: each branch of
main() mutated away turns exactly its own test red (fail 1), real code 4/4.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/scanners/ci-integration.test.mjs

@@ -1,12 +1,13 @@
 // ci-integration.test.mjs — Tests for --fail-on and --compact CI flags
-import { describe, it, afterEach, after } from 'node:test';
+import { describe, it, beforeEach, afterEach, after } from 'node:test';
 import { spawn } from 'node:child_process';
 import { strict as assert } from 'node:assert';
-import { resolve, dirname } from 'node:path';
+import { resolve, dirname, join } from 'node:path';
 import { fileURLToPath } from 'node:url';
-import { mkdirSync, writeFileSync, rmSync, readFileSync, existsSync } from 'node:fs';
+import { mkdirSync, writeFileSync, rmSync, readFileSync, existsSync, cpSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { materializeTree } from '../helpers/payload-trees.mjs';
+import { mkOwnTreeDir } from '../helpers/own-tree.mjs';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const ORCHESTRATOR = resolve(__dirname, '../../scanners/scan-orchestrator.mjs');
@@ -16,11 +17,12 @@ after(poisonedTree.cleanup);
 const POISONED = poisonedTree.dir;
 const CLEAN = resolve(__dirname, '../fixtures/posture-scan/grade-a-project');
 
-function run(args, timeout = 120000) {
+function run(args, timeout = 120000, cwd = undefined) {
   return new Promise((resolve) => {
     const chunks = [];
     const errChunks = [];
     const child = spawn('node', [ORCHESTRATOR, ...args], {
+      cwd,
       timeout,
       stdio: ['ignore', 'pipe', 'pipe'],
     });
@@ -117,36 +119,51 @@ describe('--fail-on + --compact combined', () => {
   });
 });
 
-describe('--fail-on via policy.json', () => {
-  const policyRoot = resolve(tmpdir(), `llm-security-policy-ci-${Date.now()}`);
-  const policyDir = resolve(policyRoot, '.llm-security');
+// v8.1.1: the policy file is honored only for the caller's own working tree
+// (scanners/lib/own-working-tree.mjs), so these run the orchestrator with the
+// fixture as its cwd and '.' as its target. grade-a-project is WARNING with 0
+// critical (default exit 1), so `ci.failOn: 'critical'` read from the policy
+// is the only way to get exit 0 — the test cannot pass without reading it.
+describe('--fail-on / --compact via policy.json (own working tree)', () => {
+  let ownDir;
+
+  function writePolicy(ci) {
+    mkdirSync(join(ownDir, '.llm-security'), { recursive: true });
+    writeFileSync(join(ownDir, '.llm-security', 'policy.json'), JSON.stringify({ ci }));
+  }
+
+  beforeEach(() => {
+    ownDir = mkOwnTreeDir('ci-policy-own-');
+    cpSync(CLEAN, ownDir, { recursive: true });
+  });
 
   afterEach(() => {
-    try { rmSync(policyRoot, { recursive: true }); } catch {}
+    rmSync(ownDir, { recursive: true, force: true });
+  });
+
+  it('known-positive: without policy the fixture exits 1 (WARNING, no critical)', async () => {
+    const { code, stdout } = await run(['.'], 120000, ownDir);
+    const env = JSON.parse(stdout);
+    assert.equal(env.aggregate.counts.critical, 0);
+    assert.equal(code, 1, 'WARNING verdict without --fail-on should exit 1');
   });
 
   it('reads failOn from policy.json ci section', async () => {
-    // Create a dir with policy + a file that triggers findings
-    mkdirSync(policyDir, { recursive: true });
-    writeFileSync(resolve(policyDir, 'policy.json'), JSON.stringify({
-      ci: { failOn: 'low' },
-    }));
-    // Scan grade-a fixture but pass policyRoot — policy is loaded from target
-    // Actually: policy is loaded from args.target, so we scan the policyRoot itself
-    // It will find few/no findings but the policy failOn is set
-    const { code } = await run([CLEAN, '--fail-on', 'low']);
-    // grade-a has LOW findings → exit 1
-    assert.equal(code, 1, 'should exit 1 — low findings with --fail-on low');
+    writePolicy({ failOn: 'critical' });
+    const { code } = await run(['.'], 120000, ownDir);
+    assert.equal(code, 0, 'policy ci.failOn: critical with no critical findings should exit 0');
   });
 
   it('CLI --fail-on overrides policy.json', async () => {
-    mkdirSync(policyDir, { recursive: true });
-    writeFileSync(resolve(policyDir, 'policy.json'), JSON.stringify({
-      ci: { failOn: 'critical' },
-    }));
-    // Policy says critical-only, but CLI says low — CLI wins
-    // We test by scanning the clean fixture with CLI --fail-on low
-    const { code } = await run([CLEAN, '--fail-on', 'low']);
-    assert.equal(code, 1, 'CLI --fail-on low should override policy failOn: critical');
+    writePolicy({ failOn: 'critical' });
+    const { code } = await run(['.', '--fail-on', 'medium'], 120000, ownDir);
+    assert.equal(code, 1, 'CLI --fail-on medium should override policy failOn: critical');
+  });
+
+  it('reads compact from policy.json ci section', async () => {
+    writePolicy({ compact: true });
+    const { stdout } = await run(['.'], 120000, ownDir);
+    assert.ok(stdout.includes('Verdict:'), 'policy ci.compact: true should print the compact summary');
+    assert.throws(() => JSON.parse(stdout), 'compact output should not be the JSON envelope');
   });
 });