Github user ilooner commented on a diff in the pull request:
--- Diff: exec/vector/pom.xml ---
@@ -69,6 +69,7 @@
--- End diff --
@vrozov JUnit supports including or excluding tests based on categories.
Categories are just marker interfaces that are passed to the `@Category`
annotation. For example a test class annotated with `@Category(SlowTest.Class)`
will be excluded from a Travis run since Travis excludes the SlowTest category.
All the test categories needed to be included in a common artifact since all
the drill submodules require the test categories. So the test categories were
added to drill-common.
If drill-common is not included mvn would fail with an error when running
tests marked with `@Category(SlowTest.class)` since JUnit would not be able to
find the SlowTest class.