@SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "lookupConstraints is ImmutableList")
  public List<LookupConstraint> getLookupConstraints() {
    return lookupConstraints;
  }
@Test
  public void shouldReturnKeyConstraintInt() {
    // Given:
    when(plannerOptions.getTableScansEnabled()).thenReturn(true);
    final Expression keyExp1 = new ComparisonExpression(
            Type.GREATER_THAN,
            new UnqualifiedColumnReferenceExp(ColumnName.of("K")),
            new IntegerLiteral(1)
    );
    final Expression keyExp2 = new ComparisonExpression(
            Type.EQUAL,
            new UnqualifiedColumnReferenceExp(ColumnName.of("K")),
            new IntegerLiteral(3)
    );
    final Expression expression = new LogicalBinaryExpression(
            LogicalBinaryExpression.Type.AND,
            keyExp1,
            keyExp2
    );
    QueryFilterNode filterNode = new QueryFilterNode(
            NODE_ID,
            source,
            expression,
            metaStore,
            ksqlConfig,
            false,
            plannerOptions);

    // When:
    final List<LookupConstraint> keys = filterNode.getLookupConstraints();

    // Then:
    assertThat(keys.size(), is(1));
    assertThat(keys.get(0), instanceOf(KeyConstraint.class));
    final KeyConstraint keyConstraint = (KeyConstraint) keys.get(0);
    assertThat(keyConstraint.getKey(), is(GenericKey.genericKey(3)));
    assertThat(keyConstraint.getOperator(), is(KeyConstraint.ConstraintOperator.EQUAL));
  }