Type interference issue with the WebFlux WebTestClient and Kotlin


I'm building a prototype for a new application using Spring Webflux and Kotlin. Spring Webflux contains a WebTestClient for unit tests. According to the documentation I should be able to test the results of a REST call like this:

@Test fun getVersion_SingleResult_ContentTypeJson_StatusCodeOk_ContentEqualsVersion() { //given var version = Version("Test", "1.0") val handler = ApiHandler(version!!) val client = WebTestClient.bindToRouterFunction(ApiRoutes(handler).apiRouter()).build() //expect val response = client.get().uri("/api/version/").exchange() response.expectStatus().isOk response.expectHeader().contentType(MediaType.APPLICATION_JSON_UTF8) response.expectBody(Version::class.java).isEqualTo(version) }

However, I'm running into some type interference issues. The problem is in the combination of 'expectBody' and 'isEqualTo'.

The error I get is:


Kotlin: Type inference failed: Not enough information to infer parameter T in fun isEqualTo(p0: Version!): T! Please specify it explicitly.


The used methods have the following signatures:

<B> WebTestClient.BodySpec<B, ?> expectBody(Class<B> var1); public interface BodySpec<B, S extends WebTestClient.BodySpec<B, S>> { <T extends S> T isEqualTo(B var1); }

Sadly I'm running into the limits of my knowledge of generics and the differences between Kotlin and Java which means that I'm not sure how I should specify this.



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