OptionalTest.java

OptionalTest.java

package com.fasterxml.jackson;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.util.Optional;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class OptionalTest {
  static final class Foo {
    private final Integer bar;
    private final String moo;

    Foo(Integer bar, String moo) {
      this.bar = bar;
      this.moo = moo;
    }

    public Optional<Integer> getBar() {
      return Optional.ofNullable(bar);
    }

    public String getMoo() {
      return moo;
    }
  }

  private ObjectMapper objectMapper;


  @BeforeEach
  void setup() {
    objectMapper = new ObjectMapper()
        .setSerializationInclusion(JsonInclude.Include.NON_NULL)
        .registerModule(new Jdk8Module());
  }

  @Test
  void testOptionalPresentExists() throws JsonProcessingException {
      assertEquals("{\"bar\":3}", objectMapper.writeValueAsString(new Foo(1, null)));
  }

  @Test
  void testOptionalEmptyDoesNotExist() throws JsonProcessingException {
    assertEquals("{}", objectMapper.writeValueAsString(new Foo(null, null)));
  }
}