@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.

[philwebb]

Reopening after review by @mbhave where it was pointed out that by creating another Environment subclass we're missing the ConfigurationPropertySources. Worse, we'll likely miss any updates that we make to ApplicationEnvironment etc. We're going to see if a different fix is possible.