public String process(final Expression expression) {
    return formatExpression(expression);
  }
@Test
  public void shouldGenerateCorrectCodeForIntervalUnit() {
    // Given:
    final IntervalUnit intervalUnit = new IntervalUnit(TimeUnit.DAYS);

    // When:
    final String java = sqlToJavaVisitor.process(intervalUnit);

    // Then:
    assertThat(java, containsString("TimeUnit.DAYS"));
  }