Testing spring webclient without spring context

Spring webclient is an important component in the spring framework. Its highly customizable, allows us to do perform all the http operations in a declarative way.

But the check is you cant unit test the spring webclient. To perform assertions you would likely need to use wiremock which takes a lot of time for the tests to initialize and run. This affects the motivation to perform the test driven development.

so i decided to write my own library which allows me to perform assertions on webclient call

    public WebClient build() {
        WebClient.Builder builder = this.builder
                .clientConnector(
                        new FakeHttpConnector(requestResponsesList)
                )
                .exchangeFunction(ExchangeFunctionFactory.getInstance(this));

        if (baseUrl != null) {
            builder.baseUrl(baseUrl);
        }

        return builder.build();
    }

The above snippet of code is from the library. I perform the assertions by writing a custom http connector and a exchange function to perform assertions.

How can i use it ?

it available via maven, add the below to the pom.xml file

<dependency>
  <groupId>io.github.naveen17797</groupId>
  <artifactId>fakewebclient</artifactId>
  <scope>test</scope>
</dependency>

Lets say i want to test a post request to www.google.com, i could perform assertions like this

FakeWebClientBuilder fakeWebClientBuilder = FakeWebClientBuilder.useDefaultWebClientBuilder();

        FakeRequestResponse fakeRequestResponse = new FakeRequestResponseBuilder()
        .withRequestUrl("https://google.com/foo")
        .withRequestMethod(HttpMethod.POST)
        .withRequestBody(BodyInserters.fromFormData("foo", "bar"))
        .replyWithResponse("test")
        .replyWithResponseStatusCode(200)
        .build();



        WebClient client =
        FakeWebClientBuilder.useDefaultWebClientBuilder()
        .baseUrl("https://google.com")
        .addRequestResponse(fakeRequestResponse)
        .build();


        assertEquals("test", client.method(HttpMethod.POST)
        .uri(uriBuilder -> uriBuilder.path("/foo").build())
        .body(BodyInserters.fromFormData("foo", "bar"))
        .exchange().block()
        .bodyToMono(String.class).block());

        Assertions.assertTrue(fakeWebClientBuilder.assertAllResponsesDispatched());

simple isn't it ? No more waiting for wiremock to initialize.

If you find it helpful, you can star this repo on github

https://github.com/naveen17797/fakewebclient