Server-side Java testing with Cactus - JUnit in Action - page 267

Before we begin coding the test, let's review the requirement for AdminServlet . The
servlet should extract the needed parameter containing the command to execute
from the HTTP request (in this case, the SQL command to run). Then it should fetch
the data using the extracted command. Finally, it should pass the control to the JSP
page for display, passing the fetched data. Let's call the methods corresponding to
these actions getCommand , executeCommand , and callView , respectively.
D ESIGNING THE FIRST TEST
Listing 14.3 shows the unit tests for the getCommand method. Remember that we
haven't yet written the code under test. The AdminServlet class doesn't exist, and our
code doesn't compile (yet).

Listing 14.3 Designing and testing the getCommand method

[...]
import javax.servlet.ServletException;
import org.apache.cactus.ServletTestCase;
import org.apache.cactus.WebRequest;

B

public class TestAdminServlet extends ServletTestCase {

public void beginGetCommandOk(WebRequest request) {
request.addParameter("command", "SELECT...");
}

C

public void testGetCommandOk() throws Exception {
AdminServlet servlet = new AdminServlet();
String command = servlet.getCommand(request);
assertEquals("SELECT...", command);
}

D

public void testGetCommandNotDefined {
AdminServlet servlet = new AdminServlet();
try {
servlet.getCommand(request);
fail("Command should not have existed");
} catch (ServletException expected) {
assertTrue( true );
}
}
}
This is a typical Cactus test case. We extended the ServletTestCase B , because the
component that we want to test is a servlet. We also set a request parameter in
the begin XXX method C that we assert to be present in the test XXX method D .
Once we've written the test case, we can go on and implement the bare minimum
of code that will allow us to compile the project. We need to implement a sample serv-
let with a getCommand method. Listing 14.4 shows the code.