feat(scanner): add --benchmark mode to attack-simulator with structured reporting

plugins/llm-security/tests/scanners/benchmark.test.mjs

@@ -0,0 +1,69 @@
+// benchmark.test.mjs — Tests for --benchmark mode in attack-simulator.mjs
+// Verifies: flag parsing, report schema, block rates are valid numbers
+
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { resolve } from 'node:path';
+import { execFile } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
+import { formatBenchmarkJson } from '../../scanners/attack-simulator.mjs';
+
+const __dirname = fileURLToPath(new URL('.', import.meta.url));
+const SIMULATOR = resolve(__dirname, '../../scanners/attack-simulator.mjs');
+
+function run(args) {
+  return new Promise((resolve, reject) => {
+    execFile('node', [SIMULATOR, ...args], { timeout: 120_000 }, (err, stdout, stderr) => {
+      resolve({ err, stdout, stderr, code: err?.code ?? 0 });
+    });
+  });
+}
+
+describe('attack-simulator --benchmark', () => {
+  it('--benchmark --json produces valid JSON with required fields', async () => {
+    const { stdout } = await run(['--benchmark', '--json']);
+    const d = JSON.parse(stdout);
+
+    // Meta fields
+    assert.ok(d.meta, 'Should have meta');
+    assert.ok(d.meta.timestamp, 'Should have timestamp');
+    assert.ok(d.meta.version, 'Should have version');
+    assert.ok(d.meta.node_version, 'Should have node_version');
+    assert.equal(typeof d.meta.scenarios_total, 'number');
+
+    // Summary fields
+    assert.ok(d.summary, 'Should have summary');
+    assert.equal(typeof d.summary.block_rate, 'number');
+    assert.ok(d.summary.block_rate >= 0 && d.summary.block_rate <= 1, 'block_rate should be 0-1');
+    assert.equal(typeof d.summary.adaptive_block_rate, 'number');
+    assert.ok(d.summary.adaptive_block_rate >= 0 && d.summary.adaptive_block_rate <= 1);
+    assert.equal(typeof d.summary.total_blocked, 'number');
+    assert.equal(typeof d.summary.total_bypassed, 'number');
+
+    // Categories
+    assert.ok(d.categories, 'Should have categories');
+    assert.equal(typeof d.categories, 'object');
+
+    // Methodology
+    assert.ok(d.methodology, 'Should have methodology string');
+    assert.equal(typeof d.methodology, 'string');
+  });
+
+  it('formatBenchmarkJson returns valid structure from mock data', () => {
+    const mockFixed = [
+      { id: 'S01', name: 'test', category: 'secrets', passed: true, detail: '' },
+      { id: 'S02', name: 'test2', category: 'secrets', passed: false, detail: 'gap' },
+    ];
+    const mockAdaptive = [
+      { scenarioId: 'S01', mutation: 'homoglyph', round: 2, bypassed: true },
+    ];
+    const result = formatBenchmarkJson(mockFixed, mockAdaptive, 1000);
+
+    assert.equal(result.meta.mode, 'benchmark');
+    assert.equal(result.summary.block_rate, 0.5);
+    assert.equal(typeof result.summary.adaptive_block_rate, 'number');
+    assert.ok(result.categories.secrets);
+    assert.equal(result.categories.secrets.scenarios, 2);
+    assert.equal(result.categories.secrets.blocked, 1);
+  });
+});