GUACAMOLE-2139: Automatically determine extension compatibility.

guacamole/pom.xml

@@ -374,6 +374,13 @@
             <version>1.2.2</version>
         </dependency>
 
+        <!-- JUnit for unit testing -->
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
 </project>