Java Reference
In-Depth Information
8.3.2
Pax Exam
The gold standard for
OSG
i testing tools is a tool called Pax Exam. Pax Exam is part of
a suite of
OSG
i-related tools developed by the
OPS4J
open source community. In con-
trast to other open source communities like the Apache and Eclipse Foundations,
OPS4J
has an interestingly flat structure that emphasizes open participation as well as
open consumption. There's no notion of a
committer
, no barrier to committing source
changes, and little internal hierarchy.
Pax Exam builds on other tools developed by
OPS4J
, such as Pax Runner, to pro-
vide a sophisticated framework for launching
JU
nit—or Test
NG
—tests inside an
OSG
i
framework and collecting the results. Under the covers, the Pax Exam framework
wraps test classes into a bundle (using bnd to generate the manifest), and then auto-
matically exposes the tests as
OSG
i services. Pax Exam then invokes each test in turn
and records the results.
HOW CLEAN IS YOUR FRAMEWORK?
By default, Pax Exam will start a fresh framework for each test method, which means Pax
Exam tests may run slowly if you've got a lot of them. In recent versions, you can speed
things up—at the risk of interesting side effects—by specifying an
@ExamReactor-
Strategy
annotation. You can also choose whether Pax Exam launches the
OSG
i frame-
works inside the main
JVM
or forks a new
JVM
for each framework, and runs tests by
RMI
(Remote Method Invocation). Not spawning a new
JVM
makes things far faster, and it
also means you can debug your tests without having to attach remote debuggers. But
many of the more useful options for configuring frameworks are only supported for the
remote framework case.
Which container to use is determined by which container you list in your Maven
dependency. To use the quicker nonforking container, add the following dependency:
<dependency>
<groupId>org.ops4j.pax.exam</groupId>
<artifactId>pax-exam-container-native</artifactId>
<version>${paxexamversion}</version>
<scope>test</scope>
</dependency>
To use the more powerful, but slower, Pax Runner-based container, specify the
following:
<dependency>
<groupId>org.ops4j.pax.exam</groupId>
<artifactId>pax-exam-container-paxrunner</artifactId>
<version>${paxexamversion}</version>
<scope>test</scope>
</dependency>
ENABLING TESTS FOR PAX EXAM
A
JU
nit test intended for Pax Exam has a few key differences from one that runs stand-
alone. Running your test code in an entirely different
JVM
from the one used to
launch the test, with
RMI
and all sorts of network communication going on in the
