<p>I'm trying to load test data into a test DB during a maven build for integration testing. persistence.xml is being copied to <code>target/test-classes/META-INF/</code> correctly, but I get this exception when the test is run.</p>

<blockquote>
  <p>javax.persistence.PersistenceException:
  No Persistence provider for
  EntityManager named aimDatabase</p>
</blockquote>

<p>It looks like it's not finding or loading persistence.xml.</p>

If this is on windows, you can use sysinternal's procmon to find out if it's checking the right path.
Just filter by path -> contains -> persistence.xml.  Procmon will pick up any attempts to open a file named persistenc.xml, and you can check to see the path or paths that get tried.
See here for more detail on procmon:
http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx