Travis Build flags for tests

[Eric Charles]

Hi there,

I see tests are disabled on Travis.
e.g. From 
https://s3.amazonaws.com/archive.travis-ci.org/jobs/114476198/log.txt

$ export PROFILE="-Pspark-1.5 -Phadoop-2.3 -Ppyspark"
$ export BUILD_FLAG="package -DskipTests"

Is this on purpose?