### Question:
AbstractBFEmptinessOracle extends AbstractBFOracle<A, I, D> implements EmptinessOracle<A, I, D> { @Override public @Nullable DefaultQuery<I, D> findCounterExample(A hypothesis, Collection<? extends I> inputs) { return super.findCounterExample(hypothesis, inputs); } protected  AbstractBFEmptinessOracle(MembershipOracle<I, D> membershipOracle, double multiplier); @Override boolean isCounterExample(A hypothesis, Iterable<? extends I> inputs, @Nullable D output); @Override @Nullable DefaultQuery<I, D> findCounterExample(A hypothesis, Collection<? extends I> inputs);  }### Answer:
@Test public void testFindCounterExample() { final DefaultQuery<Character, D> cex = bfeo.findCounterExample(automaton, ALPHABET); Assert.assertEquals(cex, query); }