diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9059ed2..af23970 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -40,6 +40,8 @@ jobs:
       run: pnpm build
 
     - name: Test
+      env:
+        OPENAI_KEY: ${{ secrets.OPENAI_KEY }}
       run: |
         pnpm test
         pnpm --use-node-version=14.21.3 test
diff --git a/tests/index.ts b/tests/index.ts
index 4051fea..d516409 100644
--- a/tests/index.ts
+++ b/tests/index.ts
@@ -1,5 +1,6 @@
 import { describe } from 'manten';
 
 describe('aicommits', ({ runTestSuite }) => {
+	runTestSuite(import('./specs/cli.js'));
 	runTestSuite(import('./specs/config.js'));
 });
diff --git a/tests/specs/cli.ts b/tests/specs/cli.ts
new file mode 100644
index 0000000..abf3b44
--- /dev/null
+++ b/tests/specs/cli.ts
@@ -0,0 +1,76 @@
+import { testSuite, expect } from 'manten';
+import { createFixture } from 'fs-fixture';
+import { createAicommits, createGit } from '../utils.js';
+
+const { OPENAI_KEY } = process.env;
+if (!OPENAI_KEY) {
+	throw new Error('process.env.OPENAI_KEY is necessary to run these tests');
+}
+
+export default testSuite(({ describe }) => {
+	if (process.platform === 'win32') {
+		// https://github.com/nodejs/node/issues/31409
+		console.warn('Skipping tests on Windows because Node.js spawn cant open TTYs');
+		return;
+	}
+
+	describe('CLI', async ({ test }) => {
+		const fixture = await createFixture({
+			'data.json': JSON.stringify({
+				firstName: 'Hiroki',
+			}),
+		});
+
+		const aicommits = createAicommits({
+			cwd: fixture.path,
+			home: fixture.path,
+		});
+
+		await test('Fails on non-Git project', async () => {
+			const { stdout, exitCode } = await aicommits([], { reject: false });
+			expect(exitCode).toBe(1);
+			expect(stdout).toMatch('The current directory must be a Git repository!');
+		});
+
+		const git = await createGit(fixture.path);
+
+		await test('Fails on no staged files', async () => {
+			const { stdout, exitCode } = await aicommits([], { reject: false });
+			expect(exitCode).toBe(1);
+			expect(stdout).toMatch('No staged changes found. Make sure to stage your changes with `git add`.');
+		});
+
+		await test('Commits', async () => {
+			await git('add', ['data.json']);
+
+			await aicommits([
+				'config',
+				'set',
+				`OPENAI_KEY=${OPENAI_KEY}`,
+			]);
+
+			const statusBefore = await git('status', ['--porcelain', '--untracked-files=no']);
+			expect(statusBefore.stdout).toBe('A  data.json');
+
+			const committing = aicommits();
+			committing.stdout!.on('data', (buffer) => {
+				const data = buffer.toString();
+
+				if (data.match('Yes /')) {
+					committing.stdin!.write('y');
+					committing.stdin!.end();
+				}
+			});
+
+			await committing;
+
+			const statusAfter = await git('status', ['--porcelain', '--untracked-files=no']);
+			expect(statusAfter.stdout).toBe('');
+
+			const { stdout } = await git('log', ['--oneline']);
+			console.log('Commited with:', stdout);
+		});
+
+		await fixture.rm();
+	});
+});
diff --git a/tests/specs/config.ts b/tests/specs/config.ts
index a571ef1..1e04c03 100644
--- a/tests/specs/config.ts
+++ b/tests/specs/config.ts
@@ -2,26 +2,19 @@ import fs from 'fs/promises';
 import path from 'path';
 import { testSuite, expect } from 'manten';
 import { createFixture } from 'fs-fixture';
-import { execaNode } from 'execa';
-
-const aicommitsPath = path.resolve('./dist/cli.mjs');
+import { createAicommits } from '../utils.js';
 
 export default testSuite(({ describe }) => {
 	describe('config', async ({ test }) => {
 		const fixture = await createFixture();
-		const env = {
-			// Linux
-			HOME: fixture.path,
-
-			// Windows
-			USERPROFILE: fixture.path,
-		};
+		const aicommits = createAicommits({
+			home: fixture.path,
+		});
 		const configPath = path.join(fixture.path, '.aicommits');
 		const openAiToken = 'OPENAI_KEY=sk-abc';
 
 		test('set unknown config file', async () => {
-			const { stderr } = await execaNode(aicommitsPath, ['config', 'set', 'UNKNOWN=1'], {
-				env,
+			const { stderr } = await aicommits(['config', 'set', 'UNKNOWN=1'], {
 				reject: false,
 			});
 
@@ -29,8 +22,7 @@ export default testSuite(({ describe }) => {
 		});
 
 		test('set invalid OPENAI_KEY', async () => {
-			const { stderr } = await execaNode(aicommitsPath, ['config', 'set', 'OPENAI_KEY=abc'], {
-				env,
+			const { stderr } = await aicommits(['config', 'set', 'OPENAI_KEY=abc'], {
 				reject: false,
 			});
 
@@ -38,14 +30,14 @@ export default testSuite(({ describe }) => {
 		});
 
 		await test('set config file', async () => {
-			await execaNode(aicommitsPath, ['config', 'set', openAiToken], { env });
+			await aicommits(['config', 'set', openAiToken]);
 
 			const configFile = await fs.readFile(configPath, 'utf8');
 			expect(configFile).toMatch(openAiToken);
 		});
 
 		await test('get config file', async () => {
-			const { stdout } = await execaNode(aicommitsPath, ['config', 'get', 'OPENAI_KEY'], { env });
+			const { stdout } = await aicommits(['config', 'get', 'OPENAI_KEY']);
 
 			expect(stdout).toBe(openAiToken);
 		});
@@ -53,8 +45,7 @@ export default testSuite(({ describe }) => {
 		await test('reading unknown config', async () => {
 			await fs.appendFile(configPath, 'UNKNOWN=1');
 
-			const { stdout, stderr } = await execaNode(aicommitsPath, ['config', 'get', 'UNKNOWN'], {
-				env,
+			const { stdout, stderr } = await aicommits(['config', 'get', 'UNKNOWN'], {
 				reject: false,
 			});
 
diff --git a/tests/utils.ts b/tests/utils.ts
new file mode 100644
index 0000000..3e47925
--- /dev/null
+++ b/tests/utils.ts
@@ -0,0 +1,63 @@
+import path from 'path';
+import { execa, execaNode, type Options } from 'execa';
+
+const aicommitsPath = path.resolve('./dist/cli.mjs');
+
+export const createAicommits = ({
+	cwd,
+	home,
+}: {
+	cwd?: string;
+	home: string;
+}) => {
+	const homeEnv = {
+		HOME: home, // Linux
+		USERPROFILE: home, // Windows
+	};
+
+	return (
+		args?: string[],
+		options?: Options,
+	) => execaNode(aicommitsPath, args, {
+		...options,
+		cwd,
+		extendEnv: false,
+		env: {
+			...homeEnv,
+			...options?.env,
+		},
+
+		// Block tsx nodeOptions
+		nodeOptions: [],
+	});
+};
+
+export const createGit = async (cwd: string) => {
+	const git = (
+		command: string,
+		args?: string[],
+		options?: Options,
+	) => (
+		execa(
+			'git',
+			[command, ...(args || [])],
+			{
+				cwd,
+				...options,
+			},
+		)
+	);
+
+	await git(
+		'init',
+		[
+			// In case of different default branch name
+			'--initial-branch=master',
+		],
+	);
+
+	await git('config', ['user.name', 'name']);
+	await git('config', ['user.email', 'email']);
+
+	return git;
+};