What is the difference between MockMvc and WebTestClient?

Question

When I tried to test at Spring 4.x, I used MockMvc web client, but I am reading and trying new features of Spring 5.x.

I think, WebTestClient and MockMvc are same or very similar.

What is the difference between MockMvc and WebTestClient ?

I am waiting for your answer. Thank you

Answer 1

Similarities

• Both provide a fluent-style syntax for testing web services.
• Both can or do operate in a simulated environment that bypasses the use of HTTP.

Major Differences

• WebTestClient can also be used to test real web services using HTTP.
  • Specify @SpringBootTest instead of @WebFluxText.
• WebTestClient only works if you are using Netty for your local server.
  • This feels like an artificial limitation for the test environment.
  • It is likely due to the non-blocking nature of the underlying WebClient.
• WebTestClient can test Streaming Responses

Resources

• Benefits of having HTTP endpoints return Flux/Mono instances instead of DTOs
• Unable to use reactive WebClient without spring-boot-starter-reactor-netty
• WebTestClient documentation
• Spring Boot Data Rest don't support reactive? -- limitations of Netty