diff --git a/commit-ai/test_commit.py b/commit-ai/test_commit.py
new file mode 100644
index 0000000..e16f56c
--- /dev/null
+++ b/commit-ai/test_commit.py
@@ -0,0 +1,132 @@
+"""Unit tests for commit-ai message generator."""
+
+import pytest
+from unittest.mock import patch, MagicMock
+import sys
+import os
+
+# Add parent to path for imports
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+class TestCommitAI:
+    """Tests for CommitAI class."""
+
+    @patch('subprocess.run')
+    def test_get_diff_staged(self, mock_run):
+        """Test getting staged diff."""
+        mock_run.return_value = MagicMock(stdout="+ new line\n- old line")
+        
+        from commit import CommitAI
+        ai = CommitAI()
+        diff = ai.get_diff(staged_only=True)
+        
+        assert "+ new line\n- old line" == diff
+        mock_run.assert_called()
+
+    @patch('subprocess.run')
+    def test_get_diff_all(self, mock_run):
+        """Test getting all diff."""
+        mock_run.return_value = MagicMock(stdout="+ added")
+        
+        from commit import CommitAI
+        ai = CommitAI()
+        diff = ai.get_diff(staged_only=False)
+        
+        assert "+ added" == diff
+
+    @patch('subprocess.run')
+    def test_get_branch(self, mock_run):
+        """Test getting current branch."""
+        mock_run.return_value = MagicMock(stdout="feature-branch")
+        
+        from commit import CommitAI
+        ai = CommitAI()
+        branch = ai.get_branch()
+        
+        assert "feature-branch" == branch
+
+    @patch('subprocess.run')
+    def test_get_recent_commits(self, mock_run):
+        """Test getting recent commits."""
+        mock_run.return_value = MagicMock(stdout="feat: add new\nfix: bug")
+        
+        from commit import CommitAI
+        ai = CommitAI()
+        recent = ai.get_recent_commits(count=5)
+        
+        assert "feat: add new\nfix: bug" == recent
+
+    def test_generate_commit_message_conventional(self):
+        """Test conventional commit format generation."""
+        from commit import CommitAI
+        
+        # Mock the API response
+        with patch.object(CommitAI, '__init__', lambda x: None):
+            ai = CommitAI()
+            ai.client = MagicMock()
+            
+            mock_response = MagicMock()
+            mock_response.content = [MagicMock(text="feat(api): add new endpoint")]
+            ai.client.messages.create.return_value = mock_response
+            
+            diff = "+ def new_func(): pass"
+            branch = "main"
+            recent = "feat: init"
+            
+            result = ai.generate_commit_message(diff, conventional=True, branch=branch, recent_style=recent)
+            
+            assert result == "feat(api): add new endpoint"
+
+    def test_generate_commit_message_simple(self):
+        """Test simple commit format."""
+        from commit import CommitAI
+        
+        with patch.object(CommitAI, '__init__', lambda x: None):
+            ai = CommitAI()
+            ai.client = MagicMock()
+            
+            mock_response = MagicMock()
+            mock_response.content = [MagicMock(text="Add new function")]
+            ai.client.messages.create.return_value = mock_response
+            
+            diff = "+ def new_func(): pass"
+            
+            result = ai.generate_commit_message(diff, conventional=False)
+            
+            assert result == "Add new function"
+
+    def test_empty_diff(self):
+        """Test handling empty diff."""
+        from commit import CommitAI
+        
+        with patch.object(CommitAI, '__init__', lambda x: None):
+            ai = CommitAI()
+            
+            with patch.object(ai, 'get_diff', return_value=""):
+                result = ai.generate(staged_only=True)
+                
+                assert "No changes to commit" in result
+
+    @patch('subprocess.run')
+    def test_auto_commit(self, mock_run):
+        """Test auto commit functionality."""
+        from commit import CommitAI
+        
+        with patch.object(CommitAI, '__init__', lambda x: None):
+            ai = CommitAI()
+            
+            # Mock all the methods
+            with patch.object(ai, 'get_diff', return_value="+ new"), \
+                 patch.object(ai, 'get_branch', return_value="main"), \
+                 patch.object(ai, 'get_recent_commits', return_value="init"), \
+                 patch.object(ai, 'generate_commit_message', return_value="feat: add"):
+                
+                result = ai.generate(staged_only=True, auto_commit=True)
+                
+                assert "Committed" in result
+                mock_run.assert_any_call(["git", "commit", "-m", "feat: add"], check=True)
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])