使用 jsonPath 时 springboot 集成测试失败

Question

I have worked with the intergration test in springboot and i have tried to test a get method in my controller.The method is work in postman.However it fail in test which the Json path is not found.

The tested controller method:

 @GetMapping("/product/{id}")
    public Product getproduct(@PathVariable int id){
        return productRepository.findById(id).orElse(null);
    }

My test code:

@ExtendWith(SpringExtension.class)
@WebMvcTest(OrderController.class)
class OrderControllerTest {

    @Autowired
    private MockMvc mvc;

    @MockBean
    private ProductRepository productRepository;

    @MockBean
    private CustomerRepository customerRepository;

    @Test
    void getproduct() throws Exception {
/*        RequestBuilder request= MockMvcRequestBuilders.;*/

        mvc.perform(get("/product/{pid}","201")).andDo(print())
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.productName").value("Mobile"));
    }
}

result in postman:

{
    "pid": 201,
    "productName": "Mobile",
    "quantity": 1,
    "price": 20000
}

error message:

java.lang.AssertionError: No value at JSON path "$.productName"

Answer 1

As Marko mentions here the jsonPath probably interprets the json body as a list and therefore you can try address the first object in the json body:

 .andExpect(jsonPath("$[0].productName").value("Mobile"));

Answer 2

You are using @MockBean which means you are using mocked repositories not real repositories that are connected to a database. As you have registered no behavior on the mocks it will do its default behavior which is, for Optional return an empty Optional . Which results in null being returned thus no body.

I would suggest to rewrite your controller to the following.

@GetMapping("/product/{id}")
public ResponseEntity<Product> getproduct(@PathVariable int id){
  return ResponseEntity.of(productRepository.findById(id));
}

This will probably make your test fail on the assert for OK as it will now return a 404 (NOT FOUND).

To fix your test register same behavior on the mocked repository.

@Test
void getproduct() throws Exception {
  Product p = /// Create some product
  when(productRepository.findById(201)).thenReturn(Optional.of(p));

  mvc.perform(get("/product/{pid}","201")).andDo(print())
    .andExpect(status().isOk())
    .andExpect(jsonPath("$.productName").value("Mobile"));
}

This will create the behavior you want and will return the product, which you can then assert.