Example of using Mockrunner to write JUnit tests for servlets

Employee.java

package com.pointwest.example;

public class Employee {

}

EmployeeController.java

package com.pointwest.example;

public class EmployeeController {

	public Object getEmployeeById(String id) {
		// TODO Auto-generated method stub
		return null;
	}

}

EmployeeServlet.java

package com.pointwest.example;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class EmployeeServlet
 */
public class EmployeeServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public EmployeeServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		if(null == request.getParameter("employeeId"))
			response.setStatus(500);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
	}

}

EmployeeServletTest.java

package com.pointwest.example;

import junit.framework.Assert;

import org.junit.Before;
import org.junit.Test;

import com.mockrunner.mock.web.WebMockObjectFactory;
import com.mockrunner.servlet.ServletTestModule;

public class EmployeeServletTest {

	private ServletTestModule tester;
	private WebMockObjectFactory factory;
	
	@Before
	public void setup() {
		factory = new WebMockObjectFactory();
		tester = new ServletTestModule(factory);
	}
	
	@Test
	public void doGetNullID() {
		String id = null;
		int expectedCode = 500;

		tester.addRequestParameter("employeeId", id);

		// instantiate the servlet
		tester.createServlet(EmployeeServlet.class);
		
		// call doGet
		tester.doGet();

		// assertion: status code should be 500
		Assert.assertEquals(expectedCode, factory.getMockResponse().getStatusCode());
	}

	@Test
	public void doGetValidID() {
		String id = "eliel";
		int expectedCode = 200;
		
		tester.addRequestParameter("employeeId", id);

		// instantiate the servlet
		tester.createServlet(EmployeeServlet.class);
		
		// call doGet
		tester.doGet();

		// assertion: status code should be 200
		Assert.assertEquals(expectedCode, factory.getMockResponse().getStatusCode());
	}

	@Test
	public void doGetSendsValidIDToController() {
		String id = "eliel";
		int expectedCode = 200;
		
		Employee empDetails = new Employee();
		
		// note: need to import PowerMock for this to work
		EmployeeController mockController = createMock(EmployeeController.class);
		expect(mockController.getEmployeeById(id)).andReturn(empDetails);
		replay(EmployeeController.class, mockController);

		tester.addRequestParameter("employeeId", id);

		// instantiate the servlet
		tester.createServlet(EmployeeServlet.class);
		
		// call doGet
		tester.doGet();

		verify(EmployeeController.class, mockController);
	}
}