package com.atlassian.vcache.marshallers;
   
   import com.atlassian.vcache.MarshallerException;
   import org.junit.Test;
   
   import java.util.Optional;
   
   import static org.hamcrest.Matchers.is;
   import static org.hamcrest.Matchers.notNullValue;
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertThat;
  
  public class OptionalMarshallerTest {
      // Implementation note: unable to use an empty byte array to signify that there is no value. This is because
      // it is legitimate for a Marshaller to return a zero length byte array. E.g. the StringMarshaller does this.
      // Hence this implementation uses the first byte of the array to indicate whether there is a value (or not).
      // The downside is that Marshaller interface forces us to do array copying, which should hopefully be fast.
  
      private OptionalMarshaller<String> marshaller = new OptionalMarshaller<>(new StringMarshaller());
  
      @Test
      public void emptyValue() throws MarshallerException {
          final byte[] raw = marshaller.marshall(Optional.empty());
  
          assertArrayEquals(new byte[] {0}, raw);
  
          final Optional<String> revived = marshaller.unmarshall(raw);
  
          assertThat(revived, notNullValue());
          assertThat(revived, is(Optional.empty()));
      }
  
      @Test
      public void withValue() throws MarshallerException {
          final byte[] raw = marshaller.marshall(Optional.of("claira"));
  
          assertArrayEquals(new byte[] {1, 99, 108, 97, 105, 114, 97}, raw);
  
          final Optional<String> revived = marshaller.unmarshall(raw);
  
          assertThat(revived, notNullValue());
          assertThat(revived, is(Optional.of("claira")));
      }
  
      @Test
      public void withValue_empty() throws MarshallerException {
          final byte[] raw = marshaller.marshall(Optional.of(""));
  
          assertArrayEquals(new byte[] {1}, raw);
  
          final Optional<String> revived = marshaller.unmarshall(raw);
  
          assertThat(revived, notNullValue());
          assertThat(revived, is(Optional.of("")));
      }
  }