public Expression rewrite(final Expression expression) {
    return new ExpressionTreeRewriter<>(new OperatorPlugin()::process)
        .rewrite(expression, null);
  }
@Test
  public void shouldNotReplaceStringsInFunctions() {
    // Given:
    final Expression predicate = getPredicate(
        "SELECT * FROM orders where ROWTIME = foo('2017-01-01');");

    // When:
    final Expression rewritten = rewriter.rewrite(predicate);

    // Then:
    verify(parser, never()).parse(any());
    assertThat(rewritten.toString(), is("(ORDERS.ROWTIME = FOO('2017-01-01'))"));
  }