public static Builder builder() {
    return new Builder(ImmutableList.of());
  }
@Test
  public void shouldThrowOnDuplicateValueColumnName() {
    // Given:
    final Builder builder = LogicalSchema.builder()
        .valueColumn(VALUE, BIGINT);

    // When:
    final Exception e = assertThrows(
        KsqlException.class,
        () -> builder.valueColumn(VALUE, BIGINT)
    );

    // Then:
    assertThat(e.getMessage(),
        containsString("Duplicate value columns found in schema: `value` BIGINT"));
  }