diff --git a/app/git.js b/app/git.js
index c9bc837..143e848 100644
--- a/app/git.js
+++ b/app/git.js
@@ -3,29 +3,39 @@ import fs from 'fs';
 import path from 'path';
 import { GITEA_SERVER_URL, GITEA_REPOSITORY, GITEA_TOKEN, PR_HEAD_BRANCH, FINDINGS_PATH } from './config.js';
 
-function git(args, cwd) {
-  const result = spawnSync('git', args, { cwd, encoding: 'utf8' });
-  if (result.error) throw result.error;
-  if (result.status !== 0) throw new Error((result.stderr || result.stdout || '').trim());
-  return (result.stdout || '').trim();
+function makeRunner(spawn) {
+  return function run(args, cwd, env) {
+    const opts = { cwd, encoding: 'utf8' };
+    if (env) opts.env = env;
+    const result = spawn('git', args, opts);
+    if (result.error) throw result.error;
+    if (result.status !== 0) throw new Error((result.stderr || result.stdout || '').trim());
+    return (result.stdout || '').trim();
+  };
 }
 
-export async function commitAndPush(workspace) {
-  const remoteUrl = GITEA_SERVER_URL.replace(/\/$/, '')
-    .replace('https://', `https://${GITEA_TOKEN}@`)
-    .replace('http://', `http://${GITEA_TOKEN}@`) + `/${GITEA_REPOSITORY}.git`;
+export async function commitAndPush(workspace, _spawnSync = spawnSync) {
+  const run = makeRunner(_spawnSync);
 
+  const baseUrl = GITEA_SERVER_URL.replace(/\/$/, '');
+  const remoteUrl = `${baseUrl}/${GITEA_REPOSITORY}.git`;
   const repoDir = path.join(workspace, 'repo');
 
+  // Write a temporary askpass script so the token never appears in the URL or process list
+  const askpassScript = path.join(workspace, '.git-askpass.sh');
+  fs.writeFileSync(askpassScript, `#!/bin/sh\necho "${GITEA_TOKEN}"\n`, { mode: 0o700 });
+
+  const credEnv = { ...process.env, GIT_ASKPASS: askpassScript, GIT_USERNAME: 'x-token' };
+
   try {
     if (!fs.existsSync(repoDir)) {
-      git(['clone', '--depth=1', '--branch', PR_HEAD_BRANCH, remoteUrl, repoDir], workspace);
+      run(['clone', '--depth=1', '--branch', PR_HEAD_BRANCH, remoteUrl, repoDir], workspace, credEnv);
     }
 
-    git(['config', 'user.email', 'ai-review[bot]@gitea'], repoDir);
-    git(['config', 'user.name', 'AI Review Bot'], repoDir);
-    git(['fetch', 'origin', PR_HEAD_BRANCH], repoDir);
-    git(['checkout', PR_HEAD_BRANCH], repoDir);
+    run(['config', 'user.email', 'ai-review[bot]@gitea'], repoDir);
+    run(['config', 'user.name', 'AI Review Bot'], repoDir);
+    run(['fetch', 'origin', PR_HEAD_BRANCH], repoDir, credEnv);
+    run(['checkout', PR_HEAD_BRANCH], repoDir);
 
     // 將 findings.json 從 workspace 複製到 clone 的 repo
     const srcFindings = path.join(workspace, FINDINGS_PATH);
@@ -33,19 +43,21 @@ export async function commitAndPush(workspace) {
     fs.mkdirSync(path.dirname(destFindings), { recursive: true });
     fs.copyFileSync(srcFindings, destFindings);
 
-    git(['add', FINDINGS_PATH], repoDir);
+    run(['add', FINDINGS_PATH], repoDir);
 
-    const status = git(['status', '--porcelain'], repoDir);
+    const status = run(['status', '--porcelain'], repoDir);
     if (!status) {
       console.log('  findings.json 無變更，跳過 commit');
       return;
     }
 
-    const out = git(['commit', '-m', 'chore: update ai-review findings [skip ci]'], repoDir);
+    const out = run(['commit', '-m', 'chore: update ai-review findings [skip ci]'], repoDir);
     const commitHash = out.match(/\[.+ ([a-f0-9]+)\]/)?.[1] || 'unknown';
-    git(['push', remoteUrl, PR_HEAD_BRANCH], repoDir);
+    run(['push', remoteUrl, PR_HEAD_BRANCH], repoDir, credEnv);
     console.log(`  ✅ persisted findings  commit=${commitHash}  push=${PR_HEAD_BRANCH}`);
   } catch (e) {
     console.log(`  ⚠️  Runner failed: commit/push 失敗: ${e.message}`);
+  } finally {
+    try { fs.unlinkSync(askpassScript); } catch {}
   }
 }
diff --git a/app/git.test.js b/app/git.test.js
new file mode 100644
index 0000000..d96efce
--- /dev/null
+++ b/app/git.test.js
@@ -0,0 +1,93 @@
+import { describe, it, before, after, beforeEach } from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'fs';
+import os from 'os';
+import path from 'path';
+import { commitAndPush } from './git.js';
+
+// --- helpers ---
+function makeTmpWorkspace() {
+  const ws = fs.mkdtempSync(path.join(os.tmpdir(), 'git-test-'));
+  // Pre-create repo dir so clone branch is skipped
+  fs.mkdirSync(path.join(ws, 'repo'), { recursive: true });
+  // Create a findings.json to copy
+  const findingsDir = path.join(ws, '.gitea/ai-review');
+  fs.mkdirSync(findingsDir, { recursive: true });
+  fs.writeFileSync(path.join(findingsDir, 'findings.json'), '[]');
+  return ws;
+}
+
+// Default stub: all commands succeed, status returns changes
+function makeSpawn(overrides = {}) {
+  const calls = [];
+  const spawn = (cmd, args, opts) => {
+    const key = args[0];
+    calls.push({ cmd, args, opts });
+    if (overrides[key]) return overrides[key](args, opts);
+    if (key === 'status') return { status: 0, stdout: 'M .gitea/ai-review/findings.json', stderr: '', error: null };
+    if (key === 'commit') return { status: 0, stdout: '[feature-branch abc1234] chore', stderr: '', error: null };
+    return { status: 0, stdout: '', stderr: '', error: null };
+  };
+  spawn.calls = calls;
+  return spawn;
+}
+
+describe('commitAndPush', () => {
+  let workspace;
+
+  before(() => { workspace = makeTmpWorkspace(); });
+  after(() => { fs.rmSync(workspace, { recursive: true, force: true }); });
+  beforeEach(() => {
+    // Remove leftover askpass scripts between tests
+    for (const f of fs.readdirSync(workspace)) {
+      if (f.endsWith('.git-askpass.sh')) fs.unlinkSync(path.join(workspace, f));
+    }
+  });
+
+  it('does not embed token in any git command argument', async () => {
+    const spawn = makeSpawn();
+    await commitAndPush(workspace, spawn);
+
+    for (const { args } of spawn.calls) {
+      assert.ok(!args.join(' ').includes('test-token'), `Token leaked in git args: ${args.join(' ')}`);
+    }
+  });
+
+  it('uses GIT_ASKPASS env for network operations (fetch, push, clone)', async () => {
+    const spawn = makeSpawn();
+    await commitAndPush(workspace, spawn);
+
+    const networkOps = ['fetch', 'push', 'clone'];
+    const networkCalls = spawn.calls.filter(c => networkOps.includes(c.args[0]));
+    assert.ok(networkCalls.length > 0, 'expected at least one network git call');
+
+    for (const { args, opts } of networkCalls) {
+      assert.ok(opts?.env?.GIT_ASKPASS, `GIT_ASKPASS missing for git ${args[0]}`);
+    }
+  });
+
+  it('cleans up askpass script after successful run', async () => {
+    await commitAndPush(workspace, makeSpawn());
+    const leftover = fs.readdirSync(workspace).filter(f => f.endsWith('.git-askpass.sh'));
+    assert.equal(leftover.length, 0, 'askpass script was not cleaned up');
+  });
+
+  it('cleans up askpass script even when git fails', async () => {
+    const failSpawn = () => ({ status: 1, stdout: '', stderr: 'fatal: error', error: null });
+    await commitAndPush(workspace, failSpawn);
+    const leftover = fs.readdirSync(workspace).filter(f => f.endsWith('.git-askpass.sh'));
+    assert.equal(leftover.length, 0, 'askpass script was not cleaned up after failure');
+  });
+
+  it('skips commit when status shows no changes', async () => {
+    const spawn = makeSpawn({ status: () => ({ status: 0, stdout: '', stderr: '', error: null }) });
+    await commitAndPush(workspace, spawn);
+    const commitCalled = spawn.calls.some(c => c.args[0] === 'commit');
+    assert.equal(commitCalled, false, 'commit should not run when there are no changes');
+  });
+
+  it('does not throw when git command fails', async () => {
+    const failSpawn = () => ({ status: 1, stdout: '', stderr: 'fatal: error', error: null });
+    await assert.doesNotReject(() => commitAndPush(workspace, failSpawn));
+  });
+});
diff --git a/app/package.json b/app/package.json
index b5e3877..466e7c7 100644
--- a/app/package.json
+++ b/app/package.json
@@ -2,6 +2,9 @@
   "name": "ai-code-review",
   "version": "1.0.0",
   "type": "module",
+  "scripts": {
+    "test": "node --test app/git.test.js"
+  },
   "dependencies": {
     "axios": "^1.6.7",
     "js-yaml": "^4.1.0",