private void addObject(Spatial s) {
        testObjects.add(s);
        rootNode.attachChild(s);
        physicsSpace().add(s);
    }
Test demonstrating a GImpactCollisionShape falling through a curved mesh, when using JBullet. Bullet native
does not experience this issue at the time this test was created.

@author lou
jme3-examples/src/main/java/jme3test/bullet/TestIssue1120.java