A bare-bones transaction test.

Seems to be working...

src/main/java/com/samskivert/depot/DepotRepository.java

@@ -115,6 +115,14 @@ public abstract class DepotRepository
         CONTENTS
     }
 
+    /**
+     * Returns the persistence context used by this repository.
+     */
+    public PersistenceContext ctx ()
+    {
+        return _ctx;
+    }
+
     /**
      * Loads the persistent object that matches the specified primary key.
      *