test(integration): extract benchmark fixtures from dynamic file creation

Refactors integration tests to use static fixture files instead of dynamically
writing benchmark files to temp directories at runtime.

Changes:
- Add test/integration/fixture/ directory with 35 static benchmark fixtures
- Add test/integration/fixture-paths.ts helper module with typed fixture paths
- Update integration tests to import fixtures instead of using writeFile
- Tests that need output files still use temp dirs, but only for output

This improves test reliability and makes benchmark definitions easier to
maintain and review.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: boneskull

test/integration/baseline-commands.test.ts

@@ -1,40 +1,23 @@
 import { expect } from 'bupkis';
-import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
+import { mkdir, mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { afterEach, beforeEach, describe, it } from 'node:test';
 
 import { runCommand } from '../util.js';
+import { fixtures } from './fixture-paths.js';
 
 /**
  * Integration tests for baseline management commands
  */
 
 describe('Baseline management commands', () => {
+  // Temp dir needed for baseline storage
   let tempDir: string;
-  let benchFile: string;
 
   beforeEach(async () => {
-    tempDir = await mkdtemp(join(tmpdir(), 'modestbench-baseline-test-'));
+    tempDir = await mkdtemp(join(tmpdir(), 'modestbench-baseline-'));
     await mkdir(join(tempDir, '.modestbench'), { recursive: true });
-
-    // Create a simple benchmark file
-    benchFile = join(tempDir, 'test.bench.js');
-    await writeFile(
-      benchFile,
-      `
-      export default {
-        suites: {
-          'Test Suite': {
-            benchmarks: {
-              'fast task': { fn: () => 1 + 1 },
-              'slow task': { fn: () => { let x = 0; for (let i = 0; i < 1000; i++) x += i; return x; } }
-            }
-          }
-        }
-      };
-    `,
-    );
   });
 
   afterEach(async () => {
@@ -44,7 +27,10 @@ describe('Baseline management commands', () => {
   describe('baseline set command', () => {
     it('should save most recent run as baseline', async () => {
       // Run benchmark to create history
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
 
       // Save as baseline
       const result = await runCommand(
@@ -57,7 +43,10 @@ describe('Baseline management commands', () => {
     });
 
     it('should accept --commit option', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
 
       const result = await runCommand(
         [
@@ -74,7 +63,10 @@ describe('Baseline management commands', () => {
     });
 
     it('should accept --branch option', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
 
       const result = await runCommand(
         ['baseline', 'set', 'test-baseline', '--branch', 'main'],
@@ -85,7 +77,10 @@ describe('Baseline management commands', () => {
     });
 
     it('should accept --default flag', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
 
       const result = await runCommand(
         ['baseline', 'set', 'test-baseline', '--default'],
@@ -98,7 +93,7 @@ describe('Baseline management commands', () => {
 
     it('should accept --run-id option', async () => {
       const runResult = await runCommand(
-        ['run', benchFile, '--iterations', '10'],
+        ['run', fixtures.baselineTest, '--iterations', '10'],
         tempDir,
       );
 
@@ -138,10 +133,16 @@ describe('Baseline management commands', () => {
   describe('baseline list command', () => {
     it('should list all baselines', async () => {
       // Create history and baselines
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
       await runCommand(['baseline', 'set', 'baseline1'], tempDir);
 
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
       await runCommand(['baseline', 'set', 'baseline2'], tempDir);
 
       const result = await runCommand(['baseline', 'list'], tempDir);
@@ -159,7 +160,10 @@ describe('Baseline management commands', () => {
     });
 
     it('should indicate default baseline', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
       await runCommand(
         ['baseline', 'set', 'default-baseline', '--default'],
         tempDir,
@@ -174,7 +178,10 @@ describe('Baseline management commands', () => {
 
   describe('baseline show command', () => {
     it('should show baseline details', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
       await runCommand(['baseline', 'set', 'test-baseline'], tempDir);
 
       const result = await runCommand(
@@ -200,7 +207,10 @@ describe('Baseline management commands', () => {
 
   describe('baseline delete command', () => {
     it('should delete a baseline', async () => {
-      await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+      await runCommand(
+        ['run', fixtures.baselineTest, '--iterations', '10'],
+        tempDir,
+      );
       await runCommand(['baseline', 'set', 'test-baseline'], tempDir);
 
       const result = await runCommand(
@@ -231,7 +241,10 @@ describe('Baseline management commands', () => {
     it('should analyze recent runs and suggest budgets', async () => {
       // Run benchmarks multiple times to create history
       for (let i = 0; i < 5; i++) {
-        await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+        await runCommand(
+          ['run', fixtures.baselineTest, '--iterations', '10'],
+          tempDir,
+        );
       }
 
       const result = await runCommand(['baseline', 'analyze'], tempDir);
@@ -242,7 +255,10 @@ describe('Baseline management commands', () => {
 
     it('should accept --runs option', async () => {
       for (let i = 0; i < 3; i++) {
-        await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+        await runCommand(
+          ['run', fixtures.baselineTest, '--iterations', '10'],
+          tempDir,
+        );
       }
 
       const result = await runCommand(
@@ -255,7 +271,10 @@ describe('Baseline management commands', () => {
 
     it('should accept --confidence option', async () => {
       for (let i = 0; i < 3; i++) {
-        await runCommand(['run', benchFile, '--iterations', '10'], tempDir);
+        await runCommand(
+          ['run', fixtures.baselineTest, '--iterations', '10'],
+          tempDir,
+        );
       }
 
       const result = await runCommand(