Using @AutoConfigureWebTestClient prevents separate configuration of spring.test.webtestclient.timeout from taking effect

[dimitarp]

Spring Boot 4 introduced the @AutoConfigureWebTestClient Annotation.

Using this annotation prevents binding of the configuration property spring.test.webtestclient.timeout from other properties sources (application.properties, SpringBootTest.properties(), etc.).

It seems that the current default value "" prevents the org.springframework.boot.context.properties.bind.Binder to scan other properties sources, since the value is not null. I guess the default value should be {} instead of "".

[wilkinsona]

While @AutoConfigureWebTestClient changed package in Spring Boot 4.0, it was first introduced in 2.0 and the default value has been "" since then. Are you only seeing the problem with Spring Boot 4.0 or is it just that you not tried it with earlier versions?

I guess the default value should be {} instead of "".

Unfortunately, as the attribute is a String and not a String[], {} is not a valid default.

I think that @PropertyMapping(skip = Skip.ON_DEFAULT_VALUE) would make things behave as you'd like, but I'd like to better understand the scope of the problem first and if this is a change in behavior in 4.0 or something that's always been this way.

[dimitarp]

Thanks for the quick response!

While @AutoConfigureWebTestClient changed package in Spring Boot 4.0, it was first introduced in 2.0 and the default value has been "" since then. Are you only seeing the problem with Spring Boot 4.0 or is it just that you not tried it with earlier versions?

You are of course right: @AutoConfigureWebTestClient existed in Spring Boot 3, but WebTestClientAutoConfiguration created only a MockServer-bound WebTestClient. This meant that the autoconfiguration (and the annotation) cannot be used when running a test with an embedded server (in such cases one must "manually" register a SpringBootWebTestClientBuilderCustomizer-Bean, so that the property spring.test.webtestclient.timeout is set in the WebTestClient.Builder). Anyway, I cannot tell, if the same problem exists in spring boot 3, since our tests run with an embedded server only.

WebTestClientAutoConfiguration in spring boot 4 can create embedded server bound WebTestClients. So we migrated to @AutoConfigureWebTestClient and got rid of the manual SpringBootWebTestClientBuilderCustomizer, but we noticed that the spring.test.webtestclient.timeout from the application.properties is no longer taken into account.

[dimitarp]

The following test fails with spring boot 4.0.3 and 3.5.11:

package org.example.springbootwebtestsclient

import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
// spring boot 3:
//import org.springframework.boot.test.autoconfigure.web.reactive.AutoConfigureWebTestClient
// spring boot 4:
import org.springframework.boot.webtestclient.autoconfigure.AutoConfigureWebTestClient
import org.springframework.test.web.reactive.server.WebTestClient
import java.time.Duration

@SpringBootTest(properties = ["spring.test.webtestclient.timeout=30s"])
@AutoConfigureWebTestClient
class SpringBootWebtestsclientApplicationTests {
    @Test
    fun contextLoads(@Autowired webTestClient: WebTestClient) {
        val timeout = webTestClient.javaClass.getDeclaredField("responseTimeout").let {
            it.isAccessible = true
            it.get(webTestClient)
        }
        assertThat(timeout).isEqualTo(Duration.ofSeconds(30))
    }
}

[wilkinsona]

Closing in favor of #49340.