预期：null 但是：是 <[null]> - Hamcrest 和 jsonPath

Question

我想断言休息控制器的 json 输出，但我得到 "Expected: null but: was <[null]>"。这是我的测试代码：

mockMvc.perform(post(TEST_ENDPOINT)
            .param("someParam", SOMEPARAM)
            .andDo(print())
            .andExpect(status().is2xxSuccessful())
            .andExpect(jsonPath("*.errorMessage").value(IsNull.nullValue()));

Json:

{
    "some_string": {
        "errorMessage": null
    }
}

我发现了类似的问题 How to assertThat something is null with Hamcrest?，但两个答案都不起作用。也许这是由于 jsonPath，导致它在 [] 括号中 return 空值？是断言框架的bug吗？

Answer 1

JSON根据文档，路径总是 return 一个数组，

Please note, that the return value of jsonPath is an array, which is also a valid JSON structure. So you might want to apply jsonPath to the resulting structure again or use one of your favorite array methods as sort with it.

根据此处的结果部分 [JSONPath - JSON] 的 XPath:(http://goessner.net/articles/JsonPath/index.html)

这样就排除了

的任何问题

cause it return null value in [] brackets

nullValue 应按如下方式工作

import static org.hamcrest.CoreMatchers.nullValue;
....
.andExpect(jsonPath("some_string.errorMessage", nullValue()))

或

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.nullValue;
....
.andExpect(jsonPath("some_string.errorMessage", is(nullValue())))

如此处找到的答案中所述How to assertThat something is null with Hamcrest?

预期：null 但是：是 <[null]> - Hamcrest 和 jsonPath

Expected: null but: was <[null]> - Hamcrest and jsonPath

testing

hamcrest

jsonpath