If you have ever considered to contribute to some open source projects and add your name to the committer list one day, this is a good documentation for the Solr community where you can get yourself kickstarted.
I downloaded Lucene and Solr source code locally by issuing the command:
git clone http://git-wip-us.apache.org/repos/asf/lucene-solr.git
Where http is the read-only version and you can change it to https if you are committer.
Now I have a folder called lucene-solr, and change the directory to that folder and run the command ‘ant test’ which is supposed to run all the test cases in both of the solr and lucene folder. The first downloaded folder is only 300MB-ish.
It took me literally 40 minutes to run all the test cases! And the folder exploded from 300MB to 700MB!
Then you can run the command `ant eclipse` and it is just a matter of a few seconds, you have a directory that can be loaded into Eclipse.
I located to the TestRegexpQuery.java and tried to run the junit test and somehow it failed..
Solr FAQ and this Stackoverflow question helped solve my problem by:
- checking the -ea in Eclipse preference
- add -ea to the vm argument in project setting
In the end, everything works out of box 🙂 
datafireball 