java-tutorials/javax-servlets/src/test/java/com/root/FormServletTest.java

package com.root;

import org.junit.Before;
import org.junit.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.io.StringWriter;

import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

public class FormServletTest {

    @Mock
    HttpServletRequest request;

    @Mock
    HttpServletResponse response;

    @Mock
    RequestDispatcher requestDispatcher;

    @Before
    public void setUp() throws Exception {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void testFormServlet() throws Exception {

        when(request.getParameter("height")).thenReturn("2");
        when(request.getParameter("weight")).thenReturn("80");

        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        when(response.getWriter()).thenReturn(pw);

        new FormServlet().doPost(request, response);

        verify(request).setAttribute("bmi", 20.0);

        String result = sw.getBuffer().toString().trim();
        assertEquals("20.0", result);
    }
}