public CreateTableBuilder withPkConstraintName(String pkConstraintName) {
    this.pkConstraintName = validateConstraintName(pkConstraintName);
    return this;
  }
@Test
  public void withPkConstraintName_throws_IAE_if_name_starts_with_underscore() {
    assertThatThrownBy(() -> underTest.withPkConstraintName("_a"))
      .isInstanceOf(IllegalArgumentException.class)
      .hasMessageContaining("Constraint name must not start by a number or '_', got '_a'");
  }