How do I resolve the dependencies when building git plugin for Jenkins?

How do I resolve the dependencies when building git plugin for Jenkins?

I am trying to build and install the git plugin for Jenkins.
Unfortunately, there aren't any instructions and I am new to Jenkins and
Maven.
I have found these instructions but when I get to this step mvn install it
fails on some dependencies. I've attempted many different ways to make
Maven find the jars it's looking for, but without success. Here are the
key output lines indicating the missing libraries:
Running InjectedTest
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.369 sec
<<< FAILURE!
initializationError(InjectedTest) Time elapsed: 0.017 sec <<< ERROR!
java.lang.UnsatisfiedLinkError: com.sun.jna.Native.open(Ljava/lang/String;)J
...
Running hudson.plugins.git.RevisionParameterActionTest
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.012 sec
<<< FAILURE!
init ializationError(hudson.plugins.git.RevisionParameterActionTest) Time
elapsed: 0 sec <<< ERROR!
java.lang.NoClassDefFoundError: org.jvnet.hudson.test.HudsonTestCase