diff --git a/tests/integration/test_generation.py b/tests/integration/test_generation.py
new file mode 100644
index 0000000..420adff
--- /dev/null
+++ b/tests/integration/test_generation.py
@@ -0,0 +1,147 @@
+"""Integration tests for documentation generation."""
+
+import pytest
+import tempfile
+import os
+from pathlib import Path
+
+
+class TestHTMLGeneration:
+    """Tests for HTML documentation generation."""
+
+    def test_html_generator_basic(self):
+        """Test basic HTML generation."""
+        from docgen.models import Endpoint, HTTPMethod, DocConfig
+        from docgen.generators import HTMLGenerator
+        
+        endpoints = [
+            Endpoint(
+                path="/api/users",
+                method=HTTPMethod.GET,
+                summary="Get users",
+            ),
+            Endpoint(
+                path="/api/users",
+                method=HTTPMethod.POST,
+                summary="Create user",
+            ),
+        ]
+        
+        config = DocConfig(
+            title="Test API",
+            description="A test API",
+            version="1.0.0",
+        )
+        
+        with tempfile.TemporaryDirectory() as tmpdir:
+            generator = HTMLGenerator(config)
+            output_path = generator.generate(endpoints, Path(tmpdir))
+            
+            assert output_path.exists()
+            assert output_path.name == "index.html"
+            
+            content = output_path.read_text()
+            assert "Test API" in content
+            assert "/api/users" in content
+
+    def test_html_generator_grouped_endpoints(self):
+        """Test endpoint grouping in HTML."""
+        from docgen.models import Endpoint, HTTPMethod, DocConfig
+        from docgen.generators import HTMLGenerator
+        
+        endpoints = [
+            Endpoint(
+                path="/users",
+                method=HTTPMethod.GET,
+                tags=["users"],
+            ),
+            Endpoint(
+                path="/items",
+                method=HTTPMethod.GET,
+                tags=["items"],
+            ),
+        ]
+        
+        with tempfile.TemporaryDirectory() as tmpdir:
+            generator = HTMLGenerator(DocConfig())
+            generator.generate(endpoints, Path(tmpdir))
+            
+            output_static = Path(tmpdir) / "static"
+            assert output_static.exists()
+
+
+class TestMarkdownGeneration:
+    """Tests for Markdown documentation generation."""
+
+    def test_markdown_generator_basic(self):
+        """Test basic Markdown generation."""
+        from docgen.models import Endpoint, HTTPMethod, DocConfig
+        from docgen.generators import MarkdownGenerator
+        
+        endpoints = [
+            Endpoint(
+                path="/api/users",
+                method=HTTPMethod.GET,
+                summary="Get all users",
+            ),
+        ]
+        
+        config = DocConfig(
+            title="My API",
+            description="API documentation",
+        )
+        
+        with tempfile.TemporaryDirectory() as tmpdir:
+            generator = MarkdownGenerator(config)
+            output_path = generator.generate(endpoints, Path(tmpdir))
+            
+            assert output_path.exists()
+            assert output_path.name == "README.md"
+            
+            content = output_path.read_text()
+            assert "# My API" in content
+            assert "GET" in content
+            assert "/api/users" in content
+
+
+class TestOpenAPIGeneration:
+    """Tests for OpenAPI specification generation."""
+
+    def test_openapi_generator_basic(self):
+        """Test basic OpenAPI generation."""
+        from docgen.models import Endpoint, HTTPMethod, DocConfig, Parameter, ParameterIn
+        from docgen.generators import OpenAPIGenerator
+        import json
+        
+        param = Parameter(
+            name="id",
+            type="integer",
+            required=True,
+            location=ParameterIn.PATH,
+        )
+        
+        endpoints = [
+            Endpoint(
+                path="/users/{id}",
+                method=HTTPMethod.GET,
+                summary="Get user by ID",
+                parameters=[param],
+            ),
+        ]
+        
+        config = DocConfig(
+            title="Test API",
+            version="1.0.0",
+        )
+        
+        with tempfile.TemporaryDirectory() as tmpdir:
+            generator = OpenAPIGenerator(config)
+            output_path = generator.generate(endpoints, Path(tmpdir))
+            
+            assert output_path.exists()
+            assert output_path.name == "openapi.json"
+            
+            spec = json.loads(output_path.read_text())
+            assert spec["openapi"] == "3.0.3"
+            assert spec["info"]["title"] == "Test API"
+            assert "/users/{id}" in spec["paths"]