How to create an instance of HttpServletRequest for unit testing? - unit-testing

Question

While doing some searches on SO I came across this piece of code to extract the "appUrl" from a URL:
public static String getAppUrl(HttpServletRequest request)
{
String requestURL = request.getRequestURL().toString();
String servletPath = request.getServletPath();
return requestURL.substring(0, requestURL.indexOf(servletPath));
}
My question is how does one unit test something like this? The key problem is how to create an instance of HttpServletRequest for unit testing?
Fwiw I tried some googling and most of the responses center around mocking the class. But if I mock the class so that getRequestURL returns what I want it to return (taking an example since mocking essentially overrides some methods to return canned values), then I am not really testing the code at that point. I also tried the httpunit library but that also does not help.

Answer 1

I use mockito and here is the block of code in the test method I use to mock it up:
public class TestLogin {
#Test
public void testGetMethod() throws IOException {
// Mock up HttpSession and insert it into mocked up HttpServletRequest
HttpSession session = mock(HttpSession.class);
given(session.getId()).willReturn("sessionid");
// Mock up HttpServletRequest
HttpServletRequest request = mock(HttpServletRequest.class);
given(request.getSession()).willReturn(session);
given(request.getSession(true)).willReturn(session);
HashMap<String,String[]> params = new HashMap<>();
given(request.getParameterMap()).willReturn(params);
// Mock up HttpServletResponse
HttpServletResponse response = mock(HttpServletResponse.class);
PrintWriter writer = mock(PrintWriter.class);
given(response.getWriter()).willReturn(writer);
.....
Hope that helps, I use this to test methods that require servlet objects to work.