### Question:
HardConstraintCheckerFactory implements ConstraintCheckerFactory { @Override public ConstraintChecker createConstraintCheckerWithNegation(TestModel testModel, TupleList toBeNegated) { Preconditions.check(checkValidIdentifier(testModel, toBeNegated.getId())); return new HardConstraintChecker( testModel, testModel.getExclusionConstraints(), errorConstraintsWithNegation(testModel, toBeNegated)); }  @Override ConstraintChecker createConstraintChecker(TestModel testModel); @Override ConstraintChecker createConstraintCheckerWithNegation(TestModel testModel, TupleList toBeNegated);  }### Answer:
@Test void testCreateConstraintCheckerWithNegation() { final List<TupleList> errorTupleLists = new ArrayList<>(); errorTupleLists.add(new TupleList(1, new int[]{0, 1}, Arrays.asList(new int[]{0, 0}, new int[]{1, 1}))); final TestModel model = new TestModel(2, new int[]{2, 2, 2}, Collections.emptyList(), errorTupleLists); final ConstraintChecker solver = new HardConstraintCheckerFactory() .createConstraintCheckerWithNegation(model, errorTupleLists.get(0)); final ConstraintChecker otherSolver = new HardConstraintChecker(model, model.getExclusionConstraints(), model.getErrorConstraints()); assertEquals(otherSolver.isValid(new int[]{1, 0, 1}), !solver.isValid(new int[]{1, 0, 1})); assertEquals(otherSolver.isValid(new int[]{0, 0, 1}), !solver.isValid(new int[]{0, 0, 1})); }