如何使用JsonSerializer和Mockito测试自定义JsonSerializer

Question

我有一个自定义的JsonSerialzier来以特殊格式序列化日期：

public class CustomDateJsonSerializer extends JsonSerializer<Date> {

    @Override
    public void serialize(Date value, JsonGenerator gen, SerializerProvider arg2) throws IOException, JsonProcessingException {
        String outputDateValue;
        //... do something with the Date and write the result into outputDateValue
        gen.writeString(outputDateValue);
    }
}

它工作得很好，但是如何用JUnit和Mockito测试我的代码呢？或者更确切地说，我如何模拟JsonGenerator并访问结果？

谢谢你的帮助。

Answer 1

你可以这样做：

import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.times;

@RunWith(MockitoJUnitRunner.class)
public class CustomDateJsonSerializerTest {

    @Mock
    private JsonGenerator gen;

    @Test
    public void testOutputDateValue() {
        CustomDateJsonSerializer serializer = new CustomDateJsonSerializer();
        serializer.serialize(new Date(), gen, null /*or whatever it needs to be*/);

        String expectedOutput = "whatever the correct output should be";
        verify(gen, times(1)).writeString(expectedOutput);
    }

}