Create integration-tests.mdx based on issue #267

Author: kgowru

fern/products/sdks/pages/testing/integration-tests.mdx

@@ -0,0 +1,105 @@
+---
+title: "Integration Tests"
+description: "Generate and run integration tests for your SDK"
+---
+
+# Integration Tests
+
+Fern can automatically generate integration tests for your SDK to verify that it correctly interacts with your API endpoints. These tests use a mock server to validate request/response handling without requiring a live API environment.
+
+## Supported Languages
+
+Integration tests are currently supported for:
+- TypeScript (version 1.2.4 and later)
+- C#
+
+Support for additional languages is in development.
+
+## Prerequisites
+
+- Fern CLI (latest version recommended)
+- SDK generator version requirements:
+  - TypeScript: 1.2.4 or later (1.5.0+ recommended)
+  - C#: Latest version
+
+## Generating Integration Tests
+
+1. Update your generator version in `fern.config.json`:
+
+```json
+{
+  "generators": {
+    "typescript": "1.5.0"
+  }
+}
+```
+
+2. Run the Fern generate command:
+
+```bash
+fern generate
+```
+
+This will create integration tests in your SDK's test directory.
+
+## Test Structure
+
+The generated tests include:
+
+- Mock server setup
+- Request validation
+- Response handling verification
+- Error case testing
+
+## Running Tests
+
+For TypeScript SDKs:
+
+```bash
+npm test
+```
+
+For C# SDKs:
+
+```bash
+dotnet test
+```
+
+<Note>
+  The mock server is automatically started and stopped as part of the test suite execution.
+</Note>
+
+## Custom Tests
+
+While the generated integration tests cover common API interaction patterns, you can also write custom tests to verify specific scenarios:
+
+```typescript
+describe('Custom API Tests', () => {
+  it('should handle specific business logic', async () => {
+    const client = new YourApiClient();
+    const response = await client.someEndpoint();
+    expect(response).toBeDefined();
+  });
+});
+```
+
+## Troubleshooting
+
+Common issues and solutions:
+
+- **Tests not generating**: Ensure you're using a supported generator version
+- **Mock server errors**: Verify your Fern CLI is up to date
+- **Test failures**: Check that your API definition matches the expected request/response patterns
+
+<Note>
+  If you're using an older version of the Fern CLI, you may need to update it to access the latest generator versions and features.
+</Note>
+
+## Best Practices
+
+1. Keep your generator versions up to date
+2. Run integration tests as part of your CI/CD pipeline
+3. Combine generated tests with custom test cases for comprehensive coverage
+4. Use mock server capabilities to test error scenarios
+
+For more detailed information about testing specific API scenarios, refer to the SDK documentation for your chosen language.