@SpringBootTest does not use spring.main.web-application-type properties declared in test resource files

[mat-mik]

Affects versions: 2.5.7+

I believe this is result of moving this line, see details below.

Our Spring Boot application has explicit dependency to spring-boot-starter-webflux and transitive dependency to spring-boot-starter-web, but in test/resources/application.properties we declared:

spring.main.web-application-type=reactive

and we've got test:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT) // (1)
class ReactiveOrServletApplicationTests {

    @Autowired(required = false)
    private org.springframework.boot.web.servlet.error.ErrorAttributes errorAttributesServlet; // (2)

    @Autowired(required = false)
    private org.springframework.boot.web.reactive.error.ErrorAttributes errorAttributesReactive;

    @Test
    void contextLoads() {
        assertThat(errorAttributesServlet).isNull();
        assertThat(errorAttributesReactive).isNotNull();
    }

}

Please note:

• (1) is important to declare webEnvironment because if effectively creates AbstractBeanFactory.scopes empty. That's important because of Respect WebApplicationType.REACTIVE in tests with a mock web environment #29170

• (2) we try to inject some servlet component, we expect null

Running such tests will fail, because Spring will try to define conflicting beans:

• org.springframework.boot.web.servlet.error.DefaultErrorAttributes (from ErrorMvcAutoConfiguration)
• org.springframework.boot.web.reactive.error.DefaultErrorAttributes (from ErrorWebFluxAutoConfiguration)

Such tests correctly passes on 2.5.6.

Mentioned change effectively changes what will be assigned here:

spring-boot/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

Line 332 in 7c45313

ConfigurableEnvironment environment = prepareEnvironment(listeners, bootstrapContext, applicationArguments);

Before change it was StandardEnvironment, after change it is ApplicationServletEnvironment. Difference changes evaluation (from false to true) in:

spring-boot/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnWebApplicationCondition.java

Lines 138 to 140 in 7c45313

	if (context.getEnvironment() instanceof ConfigurableWebEnvironment) {
	return ConditionOutcome.match(message.foundExactly("ConfigurableWebEnvironment"));
	}

And this messes with type of web application:

   ErrorMvcAutoConfiguration matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet' (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)

[fdimauro]

I just ran into this issue. Looks like I may not be able to update my code base to Spring Boot 2.6!

[philwebb]

@mat-mik (or @fdimauro) I'm having some trouble replicating the problem. I've created a sample application at https://github.com/philwebb/scratch-gh-29169, but I can't get the test to fail. Can you try and modify the sample so that it fails in the way that you describe?

[mat-mik]

Hi @philwebb! Thank you for looking at this issue, I submitted Pull Request to your branch - philwebb/scratch-gh-29169#1 I found out that dependency should be spring-boot-starter-web instead of spring-mvc, I changed issue description.