Server-side Java testing with Cactus - JUnit in Action - page 261

mailing list ask if people can use Cactus for testing an application based on a spe-
cific framework (like Struts, JSF , or Spring). There are quite a few tools dedicated to
such testing, and we cover some of them later in the topic. Most of those tools are
based on Cactus and require Cactus in their classpath, but again Cactus is designed
for in-container testing of the components from the Java EE spec.

14.2.2 General principles

Because Cactus is an extension of JU nit, every Cactus test is a JU nit test by itself.
The reverse isn't true; most of the JU nit tests are Cactus tests. So what distinguishes
the Cactus tests from the JU nit tests? You need to stick to a couple of rules in order
to use Cactus.
We already discussed in chapter 8 what in-container testing means. Back then, we
had a web application that uses servlets. We want to unit test the isAuthenticated
method in listing 14.1 from a SampleServlet servlet.

Listing 14.1 Sample of a servlet method to unit test

[...]
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class SampleServlet extends HttpServlet {
public boolean isAuthenticated(HttpServletRequest request) {
HttpSession session = request.getSession(false);
if (session == null ) {
return false ;
}
String authenticationAttribute =
(String) session.getAttribute("authenticated");

return Boolean.valueOf(authenticationAttribute).booleanValue();
}
}
In order to be able to test this method, we need to get hold of a valid HttpServlet-
Request object. Unfortunately, it isn't possible to call new HttpServletRequest to cre-
ate a usable request. The lifecycle of HttpServletRequest is managed by the container.
JU nit alone isn't enough to write a test for the isAuthenticated method.
So what must we do in order to obtain a valid HttpServletRequest ? Wouldn't it be
perfect if we had an HttpServletRequest object already instantiated in our test cases?
And how can we achieve this? What if we always had to extend a certain class that takes
care of providing us the server-side objects that are otherwise managed by the con-
tainer (such as HttpServletRequest )? Listing 14.2 shows a corresponding Cactus test
that tests the given servlet.