diff --git a/tests/test_cli.py b/tests/test_cli.py
new file mode 100644
index 0000000..ddd2575
--- /dev/null
+++ b/tests/test_cli.py
@@ -0,0 +1,147 @@
+"""Unit tests for the CLI module."""
+import pytest
+import tempfile
+from pathlib import Path
+from click.testing import CliRunner
+
+from api_testgen.cli.main import main
+
+
+class TestCLI:
+    """Tests for CLI commands."""
+
+    @pytest.fixture
+    def sample_spec_file(self, sample_openapi_spec):
+        """Create a temporary OpenAPI spec file."""
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.yaml', delete=False) as f:
+            import yaml
+            yaml.dump(sample_openapi_spec, f)
+            return Path(f.name)
+
+    def test_main_help(self):
+        """Test that main command shows help."""
+        runner = CliRunner()
+        result = runner.invoke(main, ["--help"])
+
+        assert result.exit_code == 0
+        assert "API TestGen" in result.output
+        assert "parse" in result.output
+        assert "generate" in result.output
+        assert "mock" in result.output
+
+    def test_parse_without_spec_shows_error(self):
+        """Test that parse without spec shows error."""
+        runner = CliRunner()
+        result = runner.invoke(main, ["parse"])
+
+        assert result.exit_code == 1
+        assert "Error: --spec option is required" in result.output
+
+    def test_parse_with_valid_spec(self, sample_spec_file):
+        """Test parsing a valid OpenAPI spec."""
+        runner = CliRunner()
+        result = runner.invoke(main, ["--spec", str(sample_spec_file), "parse"])
+
+        assert result.exit_code == 0
+        assert "Test Pet Store API" in result.output
+        assert "Endpoints: 1" in result.output
+
+    def test_generate_without_spec_shows_error(self):
+        """Test that generate without spec shows error."""
+        runner = CliRunner()
+        result = runner.invoke(main, ["generate", "pytest"])
+
+        assert result.exit_code == 1
+        assert "Error: --spec option is required" in result.output
+
+    def test_generate_pytest(self, sample_spec_file, tmp_path):
+        """Test generating pytest tests."""
+        runner = CliRunner()
+        result = runner.invoke(main, [
+            "--spec", str(sample_spec_file),
+            "--output", str(tmp_path),
+            "generate", "pytest"
+        ])
+
+        assert result.exit_code == 0
+        assert "Generated" in result.output
+        assert "test_" in result.output
+
+    def test_generate_jest(self, sample_spec_file, tmp_path):
+        """Test generating Jest tests."""
+        runner = CliRunner()
+        result = runner.invoke(main, [
+            "--spec", str(sample_spec_file),
+            "--output", str(tmp_path),
+            "generate", "jest"
+        ])
+
+        assert result.exit_code == 0
+        assert "Generated" in result.output
+        assert ".test.js" in result.output or "describe" in result.output
+
+    def test_generate_go(self, sample_spec_file, tmp_path):
+        """Test generating Go tests."""
+        runner = CliRunner()
+        result = runner.invoke(main, [
+            "--spec", str(sample_spec_file),
+            "--output", str(tmp_path),
+            "generate", "go"
+        ])
+
+        assert result.exit_code == 0
+        assert "Generated" in result.output
+        assert "_test.go" in result.output
+
+    def test_mock_without_spec_shows_error(self):
+        """Test that mock without spec shows error."""
+        runner = CliRunner()
+        result = runner.invoke(main, ["mock"])
+
+        assert result.exit_code == 1
+        assert "Error: --spec option is required" in result.output
+
+    def test_mock_generate(self, sample_spec_file, tmp_path):
+        """Test generating mock server configuration."""
+        runner = CliRunner()
+        result = runner.invoke(main, [
+            "--spec", str(sample_spec_file),
+            "--output", str(tmp_path),
+            "mock"
+        ])
+
+        assert result.exit_code == 0
+        assert "Generated" in result.output
+
+    def test_all_command(self, sample_spec_file, tmp_path):
+        """Test generating all files with 'all' command."""
+        runner = CliRunner()
+        result = runner.invoke(main, [
+            "--spec", str(sample_spec_file),
+            "--output", str(tmp_path),
+            "all", "pytest"
+        ])
+
+        assert result.exit_code == 0
+        assert "Generated" in result.output
+        assert "All files generated successfully" in result.output
+
+
+@pytest.fixture
+def sample_openapi_spec():
+    """Sample OpenAPI specification for testing."""
+    return {{
+        "openapi": "3.0.0",
+        "info": {{
+            "title": "Test Pet Store API",
+            "version": "1.0.0"
+        }},
+        "paths": {{
+            "/pets": {{
+                "get": {{
+                    "summary": "List all pets",
+                    "responses": {{"200": {{"description": "OK"}}}}
+                }}
+            }}
+        }}
+    }}