Using TDD (Test Driven Development)

If you read my previous post (WordPress Recovery), you know I've been writing some code to recover my old posts. It occurred to me I could take a small segment of what I've been doing with that code to demonstrate my approach to TDD.

Since I'm a hacker from way back, and also because I was in semi-panic mode about losing the content, I didn't approach this task with testing in mind. Now that doesn't always result in bad code: I've been doing this long enough that I can usually think through a fairly good model and code something that isn't one long method full of inline code.

In this case however, once I had started coding, I realized again that this was an opportunity to practice coding the "right" way. I had already begun with a Maven project, and generated unit tests as I went through the process of starting to build the code, so I had at least some good functioning unit tests.

WordPress Recovery

Well, I have the basics of my blog recovered now, so almost all of my posts going back several years are once again available.

In my last post titled Lesson Re-learned: Backups !, I admitted that I had committed the cardinal sin of making changes to my web site without doing a backup first (walking the tightrope without a net).

Luckily for me I had installed the WP Super Cache plugin, so all of my content actually still existed as static files, and being a bit of a hacker, I was able to throw together some code to effectively recover my posts.

Eventbrite Calendar Feed

I volunteer and provide technical support for a few non-profits, one of which is the Project Management Institute San Francisco Bay Area Chapter (http://www.pmi-sfbac.org) where I serve as the VP of Operations and CGO.

One of the moves I made in my first year with them was to migrate our event calendar to Eventbrite and Meetup. One of the gaps I found with Eventbrite is that it doesn’t have a way to provide a feed of events that can be used to update an external calendar, so I embarked on a little programming effort to create one.

Most calendar programs allow you to pull external events using the iCalendar (ics) format, and Eventbrite actually has a pretty decent API to allow you to pull the events, so I decided to write a simple PHP script to allow me generate an iCalendar feed.

This started as a simple one-off for PMI-SFBAC, but has turned into an open source project at https://code.google.com/p/eventbrite-ics/

Looking at the code, you can see it’s pretty basic, just a few PHP classes, some unit tests, Netbeans project and data.

Once the code was working, I used the iCalendar validator at http://severinghaus.org/projects/icv/ to make sure the results are good, and (at least for PMI-SFBAC) they are.

Eventually this results in a URL that I used as a feed into the All-in-One Calendar from Time.ly which lets me show events on my site’s calendar along with any other iCalendar feeds I choose to add.

To configure the All-in-One calendar, I just go to the Events in the WordPress admin panel, and add the feed.

After I add the feed I click the “Refresh” button to make sure the events show up on my calendar immediately. The events then get updated on a periodic basis (daily by default), and should keep you up to date.

Another use I put this feed to is to add the Eventbrite calendar to my Google Calendar.  I have a calendar feed from Meetup, and several of my friends so that I can quickly see what is going on that day.

The same basic idea for Google Calendar: you go to your Google Calendar, click the drop down on “Other Calendars” and choose “Add by URL”.

This gives you a nice view of events so that when you are scheduling things you can see what’s coming up that you might be interested in.

For those of you poor souls still using Outlook, the same feed can be used there as well see: http://office.microsoft.com/en-us/outlook-help/view-and-subscribe-to-internet-calendars-HA010167325.aspx

 

 

JPA and Maven and multiple persistence units

I needed to convert an existing Netbeans build to use Maven in order to stabilize the code and support Test Driven Development.

Generally this was a fairly simple process: just move all the source files and resources to the right folders in a new Maven project, and add the dependencies.

Everything was going swimmingly until I ran my first tests and got this really lovely set of errors that didn’t really tell me what was going on:

javax.annotation.processing.FilerException: Attempt to recreate a file for type com.omnistools.GaclAcl_

Now at this point I normally just do a few Google searches and find out how somebody else has solved this problem, but I really wasn’t having any luck at all finding an answer.

I did run across a couple of posts that mentioned seeing this error when using multiple persistence units in the persistence.xml.

Now my project does have a persistence unit for testing outside GlassFish (my chosen EJB container), so my first thought was to move that PU to the “right” place for my tests. So I copied the persistence.xml from src/main/resources/META-INF to the src/test/resources/META-INF and changed them so there was only one PU in each.

Well, that seemed to work for a minute, no more exception on the compile step. But now I had a new problem: I was getting an error that the PU couldn’t be found:

Tests in error:
testinsertTrackingCustomerUnFixed(com.omnistools.service.util.CompanyCustomerTrackingTest): No Persistence provider for EntityManager named ProjectTest-ejbPU
testinsertTrackingWithoutCustomerUnFixed(com.omnistools.service.util.CompanyCustomerTrackingTest): No Persistence provider for EntityManager named ProjectTest-ejbPU
testinsertTrackingCustomerFixed(com.omnistools.service.util.CompanyCustomerTrackingTest): No Persistence provider for EntityManager named ProjectTest-ejbPU
testinsertTrackingWithoutCustomerFixed(com.omnistools.service.util.CompanyCustomerTrackingTest): No Persistence provider for EntityManager named ProjectTest-ejbPU

So doing a bit of digging, it appears that the persistence.xml only gets copied once and only from the src/main/resources/META-INF folder.

I must have tried a thousand different permutations and combinations until I realized that I could have an ugly workaround that is not ideal.

The issue is that if both have the “exclude-unlisted-classes” set to true, the javac compiler tries to recreate the annotation classes during the compiler:compile and of course fails on the second PU because the classes have already been created.

So to get this to work, I set the “exclude-unlisted-classes” to false for one of the PU’s, which gets me the generated meta classes, and the tests fail (because the PU doesn’t include the required entities).

I then flip the flag back to true, and run the build again. Since the classes have already been compiled, the compile:compile doesn’t run, and the tests can succeed.

And then finally, I run across a bug report on the NetBeans site: http://netbeans.org/bugzilla/show_bug.cgi?id=183779. Now this bug talked about setting some compiler flags (in particular -proc:none which tells the compiler not to generate meta classes).

Workaround was proc:none to the javac compiler args as described here: http://maven.apache.org/plugins/maven-compiler-plugin/compile-mojo.html

        <plugin>            <groupId>org.apache.maven.plugins</groupId>            <artifactId>maven-compiler-plugin</artifactId>            <version>2.3.2</version>            <configuration>                <source>1.7</source>                <target>1.7</target>                <compilerArguments>                    <endorseddirs>${endorsed.dir}</endorseddirs>                    <proc:none/>                    <Xlint/>                    <Xlint:-path/>                    <verbose />                </compilerArguments>                <showDeprecation>true</showDeprecation>            </configuration>        </plugin>

Now my Maven build works like a charm. Both persistence units are defined in my persistence.xml, and both have the “exclude-unlisted-classes” set to false, and not only do my tests work, but the deployment is now successful as well.