    @Test
    public void testBase() {

        LazyMPEInference mpe = new LazyMPEInference(info.model, inferDB);

        // The Friends predicate should be empty.
        assertEquals(0, inferDB.countAllGroundRandomVariableAtoms(info.predicates.get("Friends")));

        mpe.inference();

        // There are multiple optimal configuration to the first round of grounding (which snowballs later),
        // but we know there should be at least 16 ground atoms and less than 20.
        int groundCount = inferDB.countAllGroundRandomVariableAtoms(info.predicates.get("Friends"));
        assertEquals(20, groundCount);

        mpe.close();
    }