public String process(final Expression expression) {
    return formatExpression(expression);
  }
@Test
  public void shouldThrowOnTimestampTimeLEQ() {
    // Given:
    final ComparisonExpression compExp = new ComparisonExpression(
        Type.LESS_THAN_OR_EQUAL,
        TIMESTAMPCOL,
        TIMECOL
    );

    // Then:
    final Exception e = assertThrows(KsqlException.class, () -> sqlToJavaVisitor.process(compExp));
    assertThat(e.getMessage(), is("Unexpected comparison to TIME: TIMESTAMP"));
  }