public sealed interface Coverage {
  record A() implements Coverage {}
  record B() implements Coverage {}
  record C() implements Coverage {}
  default String letter(){
    return switch (this){
      case A _ -> "A";
      case B _, C _ -> "Z";
    };
  }
  default String name(){
    return switch (this){
      case A _ -> "record A";
      case B _ -> "not record A";
      case C _ -> "not record A";
    };
  }
}

class CoverageTest {
  @Test
  void shouldBeAForA(){
    assertThat(new Coverage.A().letter()).isEqualTo("A");
  }
  @Test
  void shouldBeZForB(){
    assertThat(new Coverage.B().letter()).isEqualTo("Z");
  }
  @Test
  void shouldBeZForC(){
    assertThat(new Coverage.C().letter()).isEqualTo("Z");
  }
  @Test
  void shouldBeRecordAForA(){
    assertThat(new Coverage.A().name()).isEqualTo("record A");
  }
  @Test
  void shouldNotBeRecordAForB(){
    assertThat(new Coverage.B().name()).isEqualTo("not record A");
  }
  @Test
  void shouldNotBeRecordAForC(){
    assertThat(new Coverage.C().name()).isEqualTo("not record A");
  }
}