Hands-On Microservices with Kotlin

Why we mock

Let's go back to our previous test, where we tested our CustomerController in our CustomerControllerTest class, and let's review our /customers test:

@Testfun `we should GET a list of customers`() {  mockMvc.perform(get("/customers"))      .andExpect(status().isOk)      .andExpect(jsonPath("\$").isArray)      .andExpect(jsonPath("\$[0].id").value(1))      .andExpect(jsonPath("\$[0].name").value("Kotlin"))      .andExpect(jsonPath("\$[1].id").value(2))      .andExpect(jsonPath("\$[1].name").value("Spring"))      .andExpect(jsonPath("\$[2].id").value(3))      .andExpect(jsonPath("\$[2].name").value("Microservice"))      .andDo(print())}

Imagine that our customers are actually behind a database—a database that may be modified externally or outside of our tests—then our test ...