Start building against Spring Framework 6.1.18 snapshots

See gh-44491

gradle.properties

@@ -19,7 +19,7 @@ mavenVersion=3.9.4
 mockitoVersion=5.11.0
 nativeBuildToolsVersion=0.10.5
 snakeYamlVersion=2.2
-springFrameworkVersion=6.1.17
+springFrameworkVersion=6.1.18-SNAPSHOT
 springFramework60xVersion=6.0.23
 tomcatVersion=10.1.36
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -48,6 +48,7 @@ import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.BeanCurrentlyInCreationException;
+import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.UnsatisfiedDependencyException;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -221,8 +222,10 @@ class SpringApplicationTests {
 
 	@Test
 	void sourcesMustBeAccessible() {
-		assertThatIllegalArgumentException()
+		assertThatExceptionOfType(BeanDefinitionStoreException.class)
 			.isThrownBy(() -> new SpringApplication(InaccessibleConfiguration.class).run())
+			.havingRootCause()
+			.isInstanceOf(IllegalArgumentException.class)
 			.withMessageContaining("No visible constructors");
 	}
 
@@ -1602,6 +1605,11 @@ class SpringApplicationTests {
 		private InaccessibleConfiguration() {
 		}
 
+		@Bean
+		String testMessage() {
+			return "test";
+		}
+
 	}
 
 	static class SpyApplicationContext extends AnnotationConfigApplicationContext {