Unit testing a Java Servlet

Question

I would like to know what would be the best way to do unit testing of a servlet.

Testing internal methods is not a problem as long as they don\'t refer to the servl

Answer 1

I looked at the posted answers and thought that I would post a more complete solution that actually demonstrates how to do the testing using embedded GlassFish and its Apache Maven plugin.

I wrote the complete process up on my blog Using GlassFish 3.1.1 Embedded with JUnit 4.x and HtmlUnit 2.x and placed the complete project for download on Bitbucket here: image-servlet

I was looking at another post on an image servlet for JSP/JSF tags just before I saw this question. So I combined the solution I used from the other post with a complete unit tested version for this post.

How to Test

Apache Maven has a well defined lifecycle that includes test. I will use this along with another lifecycle called integration-test to implement my solution.

1. Disable standard lifecycle unit testing in the surefire plugin.
2. Add integration-test as part of the executions of the surefire-plugin
3. Add the GlassFish Maven plugin to the POM.
4. Configure GlassFish to execute during the integration-test lifecycle.
5. Run unit tests (integration tests).

GlassFish Plugin

Add this plugin as part of the .

        
            org.glassfish
            maven-embedded-glassfish-plugin
            3.1.1
            
                
                target/${project.build.finalName}
                8080
                
                test
                
                true
            
            
                
                    start
                    
                    pre-integration-test
                    
                        start
                        deploy
                    
                
                
                    stop
                    
                    post-integration-test
                    
                        undeploy
                        stop
                    
                
            
        

Surefire Plugin

Add/modify the plugin as part of the .

        
            org.apache.maven.plugins
            maven-surefire-plugin
            2.12.4
            
            
                true
            
            
                
                    integration-test
                    
                        
                        test
                    
                    
                        
                        false
                    
                
            
        

HTMLUnit

Add integration tests like the example below.

@Test
public void badRequest() throws IOException {
    webClient.getOptions().setThrowExceptionOnFailingStatusCode(false);
    webClient.getOptions().setPrintContentOnFailingStatusCode(false);
    final HtmlPage page = webClient.getPage("http://localhost:8080/test/images/");
    final WebResponse response = page.getWebResponse();
    assertEquals(400, response.getStatusCode());
    assertEquals("An image name is required.", response.getStatusMessage());
    webClient.getOptions().setThrowExceptionOnFailingStatusCode(true);
    webClient.getOptions().setPrintContentOnFailingStatusCode(true);
    webClient.closeAllWindows();
}

I wrote the complete process up on my blog Using GlassFish 3.1.1 Embedded with JUnit 4.x and HtmlUnit 2.x and placed the complete project for download on Bitbucket here: image-servlet

If you have any questions, please leave a comment. I think that this is one complete example for you to use as the basis of any testing you are planning for servlets.