Use Gradle test fixture support for spring-core

See gh-23550

build.gradle

@@ -308,6 +308,7 @@ configure([rootProject] + javaProjects) { project ->
 	group = "org.springframework"
 
 	apply plugin: "java"
+	apply plugin: "java-test-fixtures"
 	apply plugin: "checkstyle"
 	apply plugin: 'org.springframework.build.compile'
 	apply from: "${rootDir}/gradle/ide.gradle"

buildSrc/src/main/java/org/springframework/build/testsources/TestSourcesPlugin.java

@@ -55,9 +55,16 @@ public class TestSourcesPlugin implements Plugin<Project> {
 			OptionalDependenciesPlugin.OPTIONAL_CONFIGURATION_NAME,
 			JavaPlugin.TEST_COMPILE_CONFIGURATION_NAME);
 
+	/**
+	 * Projects which will not be automatically added as a test dependency.
+	 * <p>This is used to assist with the migration to Gradle test fixtures.
+	 */
+	private static final List<String> excludedProjects = Arrays.asList("spring-core");
+
+
 	@Override
 	public void apply(Project project) {
-		project.getPlugins().withType(JavaPlugin.class, (plugin) -> addTestSourcesToProject(project));
+		project.getPlugins().withType(JavaPlugin.class, plugin -> addTestSourcesToProject(project));
 	}
 
 	private void addTestSourcesToProject(Project project) {
@@ -83,13 +90,17 @@ public class TestSourcesPlugin implements Plugin<Project> {
 		}
 	}
 
-	private void addTestSourcesFromDependency(final Project currentProject, ProjectDependency dependency) {
+	@SuppressWarnings("deprecation")
+	private void addTestSourcesFromDependency(Project currentProject, ProjectDependency dependency) {
 		Project dependencyProject = dependency.getDependencyProject();
-		dependencyProject.getPlugins().withType(JavaPlugin.class, plugin -> {
-			final JavaPluginConvention javaPlugin = dependencyProject.getConvention()
-					.getPlugin(JavaPluginConvention.class);
-			SourceSetOutput test = javaPlugin.getSourceSets().findByName(SourceSet.TEST_SOURCE_SET_NAME).getOutput();
-			currentProject.getDependencies().add(JavaPlugin.TEST_COMPILE_CONFIGURATION_NAME, test);
-		});
+		if (!excludedProjects.contains(dependencyProject.getName())) {
+			dependencyProject.getPlugins().withType(JavaPlugin.class, plugin -> {
+				JavaPluginConvention javaPlugin = dependencyProject.getConvention().getPlugin(JavaPluginConvention.class);
+				SourceSetOutput test = javaPlugin.getSourceSets().findByName(SourceSet.TEST_SOURCE_SET_NAME).getOutput();
+				// System.err.println(String.format("Adding test source dependencies from %s to %s", currentProject.getName(), dependencyProject.getName()));
+				currentProject.getDependencies().add(JavaPlugin.TEST_COMPILE_CONFIGURATION_NAME, test);
+			});
+		}
 	}
+
 }

integration-tests/integration-tests.gradle

@@ -7,6 +7,7 @@ dependencies {
 	testCompile(project(":spring-beans"))
 	testCompile(project(":spring-context"))
 	testCompile(project(":spring-core"))
+	testCompile(testFixtures(project(":spring-core")))
 	testCompile(project(":spring-expression"))
 	testCompile(project(":spring-jdbc"))
 	testCompile(project(":spring-orm"))

integration-tests/src/test/java/org/springframework/aop/config/AopNamespaceHandlerScopeIntegrationTests.java

@@ -21,12 +21,12 @@ import org.junit.jupiter.api.Test;
 import org.springframework.aop.framework.Advised;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpSession;
 import org.springframework.test.context.junit.jupiter.web.SpringJUnitWebConfig;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.web.context.request.RequestContextHolder;
 import org.springframework.web.context.request.ServletRequestAttributes;
 

integration-tests/src/test/java/org/springframework/scheduling/annotation/ScheduledAndTransactionalAnnotationIntegrationTests.java

@@ -28,10 +28,10 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.stereotype.Repository;
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.tests.transaction.CallCountingTransactionManager;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.annotation.EnableTransactionManagement;
@@ -40,7 +40,7 @@ import org.springframework.transaction.annotation.Transactional;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.mockito.Mockito.mock;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Integration tests cornering bug SPR-8651, which revealed that @Scheduled methods may

spring-aop/spring-aop.gradle

@@ -6,4 +6,5 @@ dependencies {
 	optional("org.aspectj:aspectjweaver")
 	optional("org.apache.commons:commons-pool2")
 	optional("com.jamonapi:jamon")
+	testCompile(testFixtures(project(":spring-core")))
 }

spring-aop/src/test/java/org/springframework/aop/aspectj/annotation/AspectProxyFactoryTests.java

@@ -26,7 +26,7 @@ import org.aspectj.lang.annotation.Aspect;
 import org.junit.jupiter.api.Test;
 import test.aop.PerThisAspect;
 
-import org.springframework.util.SerializationTestUtils;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;

spring-aop/src/test/java/org/springframework/aop/config/AopNamespaceHandlerEventTests.java

@@ -33,7 +33,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.tests.beans.CollectingReaderEventListener;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rob Harrop

spring-aop/src/test/java/org/springframework/aop/config/AopNamespaceHandlerPointcutErrorTests.java

@@ -24,7 +24,7 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Mark Fisher

spring-aop/src/test/java/org/springframework/aop/config/TopLevelAopTagTests.java

@@ -22,7 +22,7 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Tests that the <aop:config/> element can be used as a top level element.

spring-aop/src/test/java/org/springframework/aop/framework/PrototypeTargetTests.java

@@ -25,7 +25,7 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.core.io.Resource;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Juergen Hoeller

spring-aop/src/test/java/org/springframework/aop/framework/ProxyFactoryTests.java

@@ -36,7 +36,7 @@ import org.springframework.aop.support.DefaultPointcutAdvisor;
 import org.springframework.aop.support.DelegatingIntroductionInterceptor;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.annotation.Order;
-import org.springframework.tests.TimeStamped;
+import org.springframework.core.test.fixtures.TimeStamped;
 import org.springframework.tests.aop.advice.CountingBeforeAdvice;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
 import org.springframework.tests.sample.beans.IOther;

spring-aop/src/test/java/org/springframework/aop/interceptor/ConcurrencyThrottleInterceptorTests.java

@@ -22,10 +22,10 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.aop.framework.Advised;
 import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.DerivedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/interceptor/ExposeInvocationInterceptorTests.java

@@ -25,7 +25,7 @@ import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Non-XML tests are in AbstractAopProxyTests

spring-aop/src/test/java/org/springframework/aop/scope/ScopedProxyAutowireTests.java

@@ -24,7 +24,7 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Mark Fisher

spring-aop/src/test/java/org/springframework/aop/support/AbstractRegexpMethodPointcutTests.java

@@ -21,8 +21,8 @@ import java.io.IOException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/support/AopUtilsTests.java

@@ -25,10 +25,10 @@ import org.springframework.aop.MethodMatcher;
 import org.springframework.aop.Pointcut;
 import org.springframework.aop.interceptor.ExposeInvocationInterceptor;
 import org.springframework.aop.target.EmptyTargetSource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/support/DelegatingIntroductionInterceptorTests.java

@@ -24,7 +24,8 @@ import org.junit.jupiter.api.Test;
 import org.springframework.aop.IntroductionAdvisor;
 import org.springframework.aop.IntroductionInterceptor;
 import org.springframework.aop.framework.ProxyFactory;
-import org.springframework.tests.TimeStamped;
+import org.springframework.core.test.fixtures.TimeStamped;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.aop.interceptor.SerializableNopInterceptor;
 import org.springframework.tests.sample.beans.INestedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
@@ -32,7 +33,6 @@ import org.springframework.tests.sample.beans.NestedTestBean;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SerializablePerson;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;

spring-aop/src/test/java/org/springframework/aop/support/MethodMatchersTests.java

@@ -21,11 +21,11 @@ import java.lang.reflect.Method;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.aop.MethodMatcher;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.tests.sample.beans.IOther;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/support/NameMatchMethodPointcutTests.java

@@ -21,11 +21,11 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.aop.framework.Advised;
 import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
 import org.springframework.tests.aop.interceptor.SerializableNopInterceptor;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SerializablePerson;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/support/RegexpMethodPointcutAdvisorIntegrationTests.java

@@ -22,15 +22,15 @@ import org.springframework.aop.framework.Advised;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.core.io.Resource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
 import org.springframework.tests.aop.interceptor.SerializableNopInterceptor;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rod Johnson

spring-aop/src/test/java/org/springframework/aop/target/CommonsPool2TargetSourceProxyTests.java

@@ -25,7 +25,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.tests.sample.beans.ITestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Stephane Nicoll

spring-aop/src/test/java/org/springframework/aop/target/HotSwappableTargetSourceTests.java

@@ -25,15 +25,15 @@ import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.aop.support.DefaultPointcutAdvisor;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.aop.interceptor.SerializableNopInterceptor;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SerializablePerson;
 import org.springframework.tests.sample.beans.SideEffectBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rod Johnson

spring-aop/src/test/java/org/springframework/aop/target/LazyInitTargetSourceTests.java

@@ -26,7 +26,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.tests.sample.beans.ITestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Juergen Hoeller

spring-aop/src/test/java/org/springframework/aop/target/PrototypeBasedTargetSourceTests.java

@@ -23,9 +23,9 @@ import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.SerializablePerson;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-aop/src/test/java/org/springframework/aop/target/PrototypeTargetSourceTests.java

@@ -24,7 +24,7 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.tests.sample.beans.SideEffectBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rod Johnson

spring-aop/src/test/java/org/springframework/aop/target/ThreadLocalTargetSourceTests.java

@@ -25,7 +25,7 @@ import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.SideEffectBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rod Johnson

spring-aop/src/test/java/org/springframework/aop/target/dynamic/RefreshableTargetSourceTests.java

@@ -18,10 +18,10 @@ package org.springframework.aop.target.dynamic;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Rob Harrop

spring-aop/src/test/java/org/springframework/tests/aop/interceptor/TimestampIntroductionInterceptor.java

@@ -17,7 +17,7 @@
 package org.springframework.tests.aop.interceptor;
 
 import org.springframework.aop.support.DelegatingIntroductionInterceptor;
-import org.springframework.tests.TimeStamped;
+import org.springframework.core.test.fixtures.TimeStamped;
 
 @SuppressWarnings("serial")
 public class TimestampIntroductionInterceptor extends DelegatingIntroductionInterceptor

spring-aspects/spring-aspects.gradle

@@ -24,6 +24,7 @@ dependencies {
 	optional("javax.transaction:javax.transaction-api")  // for @javax.transaction.Transactional support
 	testCompile(project(":spring-core"))  // for CodeStyleAspect
 	testCompile(project(":spring-test"))
+	testCompile(testFixtures(project(":spring-core")))
 	testCompile("javax.mail:javax.mail-api")
 	testCompileOnly("org.aspectj:aspectjrt")
 }

spring-aspects/src/test/java/org/springframework/scheduling/aspectj/AnnotationAsyncExecutionAspectTests.java

@@ -30,15 +30,15 @@ import org.springframework.aop.interceptor.SimpleAsyncUncaughtExceptionHandler;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.scheduling.annotation.AsyncResult;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.concurrent.ListenableFuture;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Unit tests for {@link AnnotationAsyncExecutionAspect}.

spring-beans/spring-beans.gradle

@@ -10,6 +10,7 @@ dependencies {
 	optional("org.codehaus.groovy:groovy-xml")
 	optional("org.jetbrains.kotlin:kotlin-reflect")
 	optional("org.jetbrains.kotlin:kotlin-stdlib")
+	testCompile(testFixtures(project(":spring-core")))
 	testCompile("javax.annotation:javax.annotation-api")
 }
 

spring-beans/src/test/java/org/springframework/beans/AbstractPropertyAccessorTests.java

@@ -47,9 +47,9 @@ import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.convert.support.GenericConversionService;
+import org.springframework.core.test.fixtures.Assume;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.Assume;
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.tests.sample.beans.BooleanTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.IndexedTestBean;
@@ -62,7 +62,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.within;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Shared tests for property accessors.

spring-beans/src/test/java/org/springframework/beans/factory/BeanFactoryUtilsTests.java

@@ -37,7 +37,7 @@ import org.springframework.tests.sample.beans.factory.DummyFactory;
 import org.springframework.util.ObjectUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rod Johnson

spring-beans/src/test/java/org/springframework/beans/factory/ConcurrentBeanFactoryTests.java

@@ -33,11 +33,11 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.beans.propertyeditors.CustomDateEditor;
-import org.springframework.tests.EnabledForTestGroups;
-import org.springframework.tests.TestGroup;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.TestGroup;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Guillaume Poirier

spring-beans/src/test/java/org/springframework/beans/factory/DefaultListableBeanFactoryTests.java

@@ -86,10 +86,11 @@ import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.convert.support.GenericConversionService;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.UrlResource;
+import org.springframework.core.test.fixtures.Assume;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.TestGroup;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.Assume;
-import org.springframework.tests.EnabledForTestGroups;
-import org.springframework.tests.TestGroup;
 import org.springframework.tests.sample.beans.DependenciesBean;
 import org.springframework.tests.sample.beans.DerivedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
@@ -98,7 +99,6 @@ import org.springframework.tests.sample.beans.NestedTestBean;
 import org.springframework.tests.sample.beans.SideEffectBean;
 import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.tests.sample.beans.factory.DummyFactory;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.util.StopWatch;
 import org.springframework.util.StringValueResolver;
 

spring-beans/src/test/java/org/springframework/beans/factory/FactoryBeanTests.java

@@ -27,11 +27,11 @@ import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.core.io.Resource;
-import org.springframework.stereotype.Component;
+import org.springframework.core.test.fixtures.stereotype.Component;
 import org.springframework.util.Assert;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rob Harrop

spring-beans/src/test/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessorTests.java

@@ -68,12 +68,12 @@ import org.springframework.core.Ordered;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.annotation.Order;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.IndexedTestBean;
 import org.springframework.tests.sample.beans.NestedTestBean;
 import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.util.ReflectionUtils;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-beans/src/test/java/org/springframework/beans/factory/annotation/CustomAutowireConfigurerTests.java

@@ -25,7 +25,7 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Unit tests for {@link CustomAutowireConfigurer}.

spring-beans/src/test/java/org/springframework/beans/factory/annotation/InjectAnnotationBeanPostProcessorTests.java

@@ -40,11 +40,11 @@ import org.springframework.beans.factory.support.AutowireCandidateQualifier;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.IndexedTestBean;
 import org.springframework.tests.sample.beans.NestedTestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-beans/src/test/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBeanTests.java

@@ -25,7 +25,7 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Unit tests for {@link FieldRetrievingFactoryBean}.

spring-beans/src/test/java/org/springframework/beans/factory/config/ObjectFactoryCreatingFactoryBeanTests.java

@@ -28,13 +28,13 @@ import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
-import org.springframework.util.SerializationTestUtils;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Colin Sampaleanu

spring-beans/src/test/java/org/springframework/beans/factory/config/PropertiesFactoryBeanTests.java

@@ -23,7 +23,7 @@ import org.junit.jupiter.api.Test;
 import org.springframework.core.io.Resource;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Unit tests for {@link PropertiesFactoryBean}.

spring-beans/src/test/java/org/springframework/beans/factory/config/PropertyPathFactoryBeanTests.java

@@ -25,7 +25,7 @@ import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Unit tests for {@link PropertyPathFactoryBean}.

spring-beans/src/test/java/org/springframework/beans/factory/config/PropertyResourceConfigurerTests.java

@@ -47,7 +47,7 @@ import org.springframework.util.StringUtils;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.springframework.beans.factory.support.BeanDefinitionBuilder.genericBeanDefinition;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Unit tests for various {@link PropertyResourceConfigurer} implementations including:

spring-beans/src/test/java/org/springframework/beans/factory/config/SimpleScopeTests.java

@@ -28,7 +28,7 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * Simple test to illustrate and verify scope usage.

spring-beans/src/test/java/org/springframework/beans/factory/parsing/CustomProblemReporterTests.java

@@ -27,7 +27,7 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import static org.springframework.core.test.fixtures.io.ResourceTestUtils.qualifiedResource;
 
 /**
  * @author Rob Harrop

spring-beans/src/test/java/org/springframework/beans/factory/support/BeanFactoryGenericsTests.java

@@ -49,7 +49,7 @@ import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.UrlResource;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.tests.sample.beans.GenericBean;
 import org.springframework.tests.sample.beans.GenericIntegerBean;
 import org.springframework.tests.sample.beans.GenericSetOfIntegerBean;
@@ -57,7 +57,7 @@ import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.springframework.tests.TestGroup.LONG_RUNNING;
+import static org.springframework.core.test.fixtures.TestGroup.LONG_RUNNING;
 
 /**
  * @author Juergen Hoeller

spring-context-indexer/src/test/java/org/springframework/context/index/sample/SampleNone.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@
 package org.springframework.context.index.sample;
 
 import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.core.type.Scope;
 
 /**
  * Candidate with no matching annotation.

spring-context-indexer/src/test/java/org/springframework/context/index/sample/Scope.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2002-2009 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.index.sample;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Copy of the {@code @Scope} annotation for testing purposes.
+ */
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Scope {
+
+	String value() default "singleton";
+
+}

spring-context-support/spring-context-support.gradle

@@ -15,6 +15,7 @@ dependencies {
 	optional("org.codehaus.fabric3.api:commonj")
 	optional("org.freemarker:freemarker")
 	testCompile(project(":spring-context"))
+	testCompile(testFixtures(project(":spring-core")))
 	testCompile("org.hsqldb:hsqldb")
 	testCompile("org.hibernate:hibernate-validator")
 	testCompile("javax.annotation:javax.annotation-api")

spring-context-support/src/test/java/org/springframework/cache/ehcache/EhCacheCacheTests.java

@@ -26,10 +26,10 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.cache.AbstractCacheTests;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.LONG_RUNNING;
+import static org.springframework.core.test.fixtures.TestGroup.LONG_RUNNING;
 
 /**
  * @author Costin Leau

spring-context-support/src/test/java/org/springframework/scheduling/quartz/QuartzSupportTests.java

@@ -37,8 +37,8 @@ import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.core.task.TaskExecutor;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -46,7 +46,7 @@ import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Juergen Hoeller

spring-context-support/src/test/java/org/springframework/validation/beanvalidation2/SpringValidatorAdapterTests.java

@@ -52,8 +52,8 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
 import org.springframework.context.support.StaticMessageSource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.util.ObjectUtils;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.validation.BeanPropertyBindingResult;
 import org.springframework.validation.FieldError;
 import org.springframework.validation.beanvalidation.SpringValidatorAdapter;

spring-context/spring-context.gradle

@@ -26,6 +26,7 @@ dependencies {
 	optional("org.jetbrains.kotlin:kotlin-reflect")
 	optional("org.jetbrains.kotlin:kotlin-stdlib")
 	optional("org.reactivestreams:reactive-streams")
+	testCompile(testFixtures(project(":spring-core")))
 	testCompile("io.projectreactor:reactor-core")
 	testCompile("org.codehaus.groovy:groovy-jsr223")
 	testCompile("org.codehaus.groovy:groovy-test")

spring-context/src/test/java/org/springframework/aop/aspectj/autoproxy/AspectJAutoProxyCreatorTests.java

@@ -50,10 +50,10 @@ import org.springframework.core.NestedRuntimeException;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.test.fixtures.Assume;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.TestGroup;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.Assume;
-import org.springframework.tests.EnabledForTestGroups;
-import org.springframework.tests.TestGroup;
 import org.springframework.tests.sample.beans.INestedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.NestedTestBean;

spring-context/src/test/java/org/springframework/aop/framework/AbstractAopProxyTests.java

@@ -57,10 +57,11 @@ import org.springframework.aop.support.Pointcuts;
 import org.springframework.aop.support.StaticMethodMatcherPointcutAdvisor;
 import org.springframework.aop.target.HotSwappableTargetSource;
 import org.springframework.aop.target.SingletonTargetSource;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.TestGroup;
+import org.springframework.core.test.fixtures.TimeStamped;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.EnabledForTestGroups;
-import org.springframework.tests.TestGroup;
-import org.springframework.tests.TimeStamped;
 import org.springframework.tests.aop.advice.CountingAfterReturningAdvice;
 import org.springframework.tests.aop.advice.CountingBeforeAdvice;
 import org.springframework.tests.aop.advice.MethodCounter;
@@ -73,7 +74,6 @@ import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SerializablePerson;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.util.StopWatch;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -765,7 +765,7 @@ public abstract class AbstractAopProxyTests {
 		@SuppressWarnings("serial")
 		class MyDi extends DelegatingIntroductionInterceptor implements TimeStamped {
 			/**
-			 * @see test.util.TimeStamped#getTimeStamp()
+			 * @see org.springframework.core.test.fixtures.util.TimeStamped#getTimeStamp()
 			 */
 			@Override
 			public long getTimeStamp() {

spring-context/src/test/java/org/springframework/aop/framework/ProxyFactoryBeanTests.java

@@ -48,8 +48,9 @@ import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.TestListener;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.test.fixtures.TimeStamped;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.TimeStamped;
 import org.springframework.tests.aop.advice.CountingBeforeAdvice;
 import org.springframework.tests.aop.advice.MyThrowsHandler;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
@@ -58,7 +59,6 @@ import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SideEffectBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-context/src/test/java/org/springframework/aop/framework/autoproxy/BeanNameAutoProxyCreatorTests.java

@@ -26,7 +26,7 @@ import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
-import org.springframework.tests.TimeStamped;
+import org.springframework.core.test.fixtures.TimeStamped;
 import org.springframework.tests.aop.advice.CountingBeforeAdvice;
 import org.springframework.tests.aop.interceptor.NopInterceptor;
 import org.springframework.tests.sample.beans.ITestBean;

spring-context/src/test/java/org/springframework/aop/scope/ScopedProxyTests.java

@@ -27,10 +27,10 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.context.SimpleMapScope;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-context/src/test/java/org/springframework/aop/target/CommonsPool2TargetSourceTests.java

@@ -27,10 +27,10 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.Person;
 import org.springframework.tests.sample.beans.SerializablePerson;
 import org.springframework.tests.sample.beans.SideEffectBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-context/src/test/java/org/springframework/beans/factory/xml/XmlBeanFactoryTests.java

@@ -55,6 +55,7 @@ import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.UrlResource;
 import org.springframework.core.io.support.EncodedResource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.DependenciesBean;
 import org.springframework.tests.sample.beans.DerivedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
@@ -64,7 +65,6 @@ import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.tests.sample.beans.factory.DummyFactory;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.FileCopyUtils;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.util.StopWatch;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-context/src/test/java/org/springframework/context/annotation/AnnotationProcessorPerformanceTests.java

@@ -34,13 +34,13 @@ import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.support.GenericApplicationContext;
-import org.springframework.tests.Assume;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.Assume;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Juergen Hoeller

spring-context/src/test/java/org/springframework/context/annotation/CommonAnnotationBeanPostProcessorTests.java

@@ -37,13 +37,13 @@ import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.jndi.support.SimpleJndiBeanFactory;
 import org.springframework.tests.mock.jndi.ExpectedLookupTemplate;
 import org.springframework.tests.sample.beans.INestedTestBean;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.NestedTestBean;
 import org.springframework.tests.sample.beans.TestBean;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

spring-context/src/test/java/org/springframework/context/annotation/ComponentScanAnnotationIntegrationTests.java

@@ -55,11 +55,11 @@ import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.Environment;
 import org.springframework.core.env.Profiles;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.TypeFilter;
 import org.springframework.tests.context.SimpleMapScope;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.beans.factory.support.BeanDefinitionBuilder.genericBeanDefinition;

spring-context/src/test/java/org/springframework/context/annotation/ComponentScanParserScopedProxyTests.java

@@ -23,8 +23,8 @@ import org.junit.jupiter.api.Test;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.context.SimpleMapScope;
-import org.springframework.util.SerializationTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-context/src/test/java/org/springframework/context/expression/ApplicationContextExpressionTests.java

@@ -51,15 +51,15 @@ import org.springframework.core.convert.support.GenericConversionService;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.EncodedResource;
-import org.springframework.tests.Assume;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.Assume;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.util.FileCopyUtils;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.util.StopWatch;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Juergen Hoeller

spring-context/src/test/java/org/springframework/context/expression/EnvironmentAccessorIntegrationTests.java

@@ -21,7 +21,7 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.GenericApplicationContext;
-import org.springframework.mock.env.MockPropertySource;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-context/src/test/java/org/springframework/context/support/DefaultLifecycleProcessorTests.java

@@ -27,10 +27,10 @@ import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.Lifecycle;
 import org.springframework.context.LifecycleProcessor;
 import org.springframework.context.SmartLifecycle;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Mark Fisher

spring-context/src/test/java/org/springframework/context/support/EnvironmentSecurityManagerIntegrationTests.java

@@ -28,13 +28,12 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.annotation.AnnotatedBeanDefinitionReader;
 import org.springframework.context.annotation.Profile;
 import org.springframework.core.env.AbstractEnvironment;
-import org.springframework.core.env.StandardEnvironmentTests;
+import org.springframework.core.test.fixtures.env.EnvironmentTestUtils;
 import org.springframework.stereotype.Component;
 
 import static java.lang.String.format;
 import static org.assertj.core.api.Assertions.assertThat;
 
-
 /**
  * Tests integration between Environment and SecurityManagers. See SPR-9970.
  *
@@ -50,7 +49,7 @@ public class EnvironmentSecurityManagerIntegrationTests {
 	@BeforeEach
 	public void setUp() {
 		originalSecurityManager = System.getSecurityManager();
-		env = StandardEnvironmentTests.getModifiableSystemEnvironment();
+		env = EnvironmentTestUtils.getModifiableSystemEnvironment();
 		env.put(AbstractEnvironment.ACTIVE_PROFILES_PROPERTY_NAME, "p1");
 	}
 

spring-context/src/test/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurerTests.java

@@ -29,8 +29,8 @@ import org.springframework.core.env.PropertySource;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 import org.springframework.mock.env.MockEnvironment;
-import org.springframework.mock.env.MockPropertySource;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-context/src/test/java/org/springframework/mock/env/MockEnvironment.java

@@ -18,6 +18,7 @@ package org.springframework.mock.env;
 
 import org.springframework.core.env.AbstractEnvironment;
 import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 
 /**
  * Simple {@link ConfigurableEnvironment} implementation exposing

spring-context/src/test/java/org/springframework/scheduling/annotation/EnableSchedulingTests.java

@@ -26,16 +26,16 @@ import org.junit.jupiter.api.Test;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.scheduling.TaskScheduler;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.scheduling.config.IntervalTask;
 import org.springframework.scheduling.config.ScheduledTaskHolder;
 import org.springframework.scheduling.config.ScheduledTaskRegistrar;
 import org.springframework.scheduling.config.TaskManagementConfigUtils;
-import org.springframework.tests.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Tests use of @EnableScheduling on @Configuration classes.

spring-context/src/test/java/org/springframework/scheduling/concurrent/ScheduledExecutorFactoryBeanTests.java

@@ -23,7 +23,7 @@ import java.util.concurrent.ThreadFactory;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.core.task.NoOpRunnable;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
@@ -32,7 +32,7 @@ import static org.mockito.Mockito.atLeast;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Rick Evans

spring-context/src/test/java/org/springframework/scripting/support/ScriptFactoryPostProcessorTests.java

@@ -24,16 +24,16 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.scripting.Messenger;
 import org.springframework.scripting.ScriptCompilationException;
 import org.springframework.scripting.groovy.GroovyScriptFactory;
-import org.springframework.tests.EnabledForTestGroups;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.Mockito.mock;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * @author Rick Evans

spring-context/src/test/java/org/springframework/validation/beanvalidation/SpringValidatorAdapterTests.java

@@ -50,8 +50,8 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
 import org.springframework.context.support.StaticMessageSource;
+import org.springframework.core.test.fixtures.io.SerializationTestUtils;
 import org.springframework.util.ObjectUtils;
-import org.springframework.util.SerializationTestUtils;
 import org.springframework.validation.BeanPropertyBindingResult;
 import org.springframework.validation.FieldError;
 

spring-context/src/test/kotlin/org/springframework/context/support/BeanDefinitionDslTests.kt

@@ -25,7 +25,7 @@ import org.springframework.beans.factory.getBean
 import org.springframework.context.support.BeanDefinitionDsl.*
 import org.springframework.core.env.SimpleCommandLinePropertySource
 import org.springframework.core.env.get
-import org.springframework.mock.env.MockPropertySource
+import org.springframework.core.test.fixtures.env.MockPropertySource
 import java.util.stream.Collectors
 
 @Suppress("UNUSED_EXPRESSION")

spring-core/spring-core.gradle

@@ -60,6 +60,12 @@ dependencies {
 	testCompile("javax.xml.bind:jaxb-api")
 	testCompile("com.fasterxml.woodstox:woodstox-core")
 	testCompile(project(":kotlin-coroutines"))
+	testFixturesApi("org.junit.jupiter:junit-jupiter-api")
+	testFixturesApi("org.junit.jupiter:junit-jupiter-params")
+	testFixturesImplementation("com.google.code.findbugs:jsr305")
+	testFixturesImplementation("io.projectreactor:reactor-test")
+	testFixturesImplementation("org.assertj:assertj-core")
+	testFixturesImplementation("org.xmlunit:xmlunit-assertj")
 }
 
 jar {

spring-core/src/test/java/example/type/AspectJTypeFilterTestsTypes.java

@@ -16,7 +16,7 @@
 
 package example.type;
 
-import org.springframework.stereotype.Component;
+import org.springframework.core.test.fixtures.stereotype.Component;
 
 /**
  * We must use a standalone set of types to ensure that no one else is loading

spring-core/src/test/java/org/springframework/core/annotation/AnnotatedElementUtilsTests.java

@@ -42,10 +42,10 @@ import org.springframework.core.annotation.AnnotationUtilsTests.ExtendsBaseClass
 import org.springframework.core.annotation.AnnotationUtilsTests.ImplementsInterfaceWithGenericAnnotatedMethod;
 import org.springframework.core.annotation.AnnotationUtilsTests.WebController;
 import org.springframework.core.annotation.AnnotationUtilsTests.WebMapping;
+import org.springframework.core.test.fixtures.stereotype.Component;
+import org.springframework.core.test.fixtures.stereotype.Indexed;
 import org.springframework.lang.NonNullApi;
 import org.springframework.lang.Nullable;
-import org.springframework.stereotype.Component;
-import org.springframework.stereotype.Indexed;
 import org.springframework.util.MultiValueMap;
 
 import static java.util.Arrays.asList;

spring-core/src/test/java/org/springframework/core/annotation/AnnotationUtilsTests.java

@@ -39,8 +39,8 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.subpackage.NonPublicAnnotatedClass;
+import org.springframework.core.test.fixtures.stereotype.Component;
 import org.springframework.lang.NonNullApi;
-import org.springframework.stereotype.Component;
 
 import static java.util.Arrays.asList;
 import static java.util.Arrays.stream;
@@ -928,7 +928,7 @@ class AnnotationUtilsTests {
 		Map<String, Object> map = Collections.singletonMap(VALUE, 42L);
 		assertThatIllegalStateException().isThrownBy(() ->
 				synthesizeAnnotation(map, Component.class, null).value())
-			.withMessageContaining("Attribute 'value' in annotation org.springframework.stereotype.Component "
+			.withMessageContaining("Attribute 'value' in annotation org.springframework.core.test.fixtures.stereotype.Component "
 					+ "should be compatible with java.lang.String but a java.lang.Long value was returned");
 	}
 

spring-core/src/test/java/org/springframework/core/annotation/MergedAnnotationsTests.java

@@ -43,9 +43,9 @@ import org.springframework.core.Ordered;
 import org.springframework.core.annotation.MergedAnnotation.Adapt;
 import org.springframework.core.annotation.MergedAnnotations.SearchStrategy;
 import org.springframework.core.annotation.subpackage.NonPublicAnnotatedClass;
+import org.springframework.core.test.fixtures.stereotype.Component;
+import org.springframework.core.test.fixtures.stereotype.Indexed;
 import org.springframework.lang.Nullable;
-import org.springframework.stereotype.Component;
-import org.springframework.stereotype.Indexed;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ReflectionUtils;
@@ -1770,7 +1770,7 @@ class MergedAnnotationsTests {
 		MergedAnnotation<Component> annotation = MergedAnnotation.of(Component.class, map);
 		assertThatIllegalStateException().isThrownBy(() -> annotation.synthesize().value())
 				.withMessage("Attribute 'value' in annotation " +
-						"org.springframework.stereotype.Component should be " +
+						"org.springframework.core.test.fixtures.stereotype.Component should be " +
 						"compatible with java.lang.String but a java.lang.Long value was returned");
 	}
 

spring-core/src/test/java/org/springframework/core/codec/ByteArrayDecoderTests.java

@@ -24,6 +24,7 @@ import reactor.core.publisher.Flux;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.test.fixtures.codec.AbstractDecoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/ByteArrayEncoderTests.java

@@ -22,6 +22,7 @@ import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Flux;
 
 import org.springframework.core.ResolvableType;
+import org.springframework.core.test.fixtures.codec.AbstractEncoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/ByteBufferDecoderTests.java

@@ -25,6 +25,7 @@ import reactor.core.publisher.Flux;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.test.fixtures.codec.AbstractDecoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/ByteBufferEncoderTests.java

@@ -23,6 +23,7 @@ import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Flux;
 
 import org.springframework.core.ResolvableType;
+import org.springframework.core.test.fixtures.codec.AbstractEncoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/CharSequenceEncoderTests.java

@@ -23,6 +23,7 @@ import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Flux;
 
 import org.springframework.core.ResolvableType;
+import org.springframework.core.test.fixtures.codec.AbstractEncoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static java.nio.charset.StandardCharsets.ISO_8859_1;

spring-core/src/test/java/org/springframework/core/codec/DataBufferDecoderTests.java

@@ -25,6 +25,7 @@ import reactor.core.publisher.Flux;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.core.test.fixtures.codec.AbstractDecoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/DataBufferEncoderTests.java

@@ -24,6 +24,7 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.test.fixtures.codec.AbstractEncoderTests;
 import org.springframework.util.MimeTypeUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;

spring-core/src/test/java/org/springframework/core/codec/ResourceDecoderTests.java

@@ -28,6 +28,7 @@ import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.InputStreamResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.test.fixtures.codec.AbstractDecoderTests;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.StreamUtils;
 

spring-core/src/test/java/org/springframework/core/codec/ResourceEncoderTests.java

@@ -28,6 +28,7 @@ import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.InputStreamResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.test.fixtures.codec.AbstractEncoderTests;
 import org.springframework.lang.Nullable;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;

spring-core/src/test/java/org/springframework/core/codec/ResourceRegionEncoderTests.java

@@ -29,11 +29,11 @@ import reactor.test.StepVerifier;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
-import org.springframework.core.io.buffer.AbstractLeakCheckingTests;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferUtils;
-import org.springframework.core.io.buffer.support.DataBufferTestUtils;
 import org.springframework.core.io.support.ResourceRegion;
+import org.springframework.core.test.fixtures.io.buffer.AbstractLeakCheckingTests;
+import org.springframework.core.test.fixtures.io.buffer.DataBufferTestUtils;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 

spring-core/src/test/java/org/springframework/core/codec/StringDecoderTests.java

@@ -30,6 +30,7 @@ import reactor.test.StepVerifier;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferLimitException;
+import org.springframework.core.test.fixtures.codec.AbstractDecoderTests;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 

spring-core/src/test/java/org/springframework/core/convert/converter/DefaultConversionServiceTests.java

@@ -51,13 +51,13 @@ import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.support.DefaultConversionService;
-import org.springframework.tests.EnabledForTestGroups;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StopWatch;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Unit tests for {@link DefaultConversionService}.

spring-core/src/test/java/org/springframework/core/convert/support/GenericConversionServiceTests.java

@@ -43,8 +43,8 @@ import org.springframework.core.convert.converter.ConverterFactory;
 import org.springframework.core.convert.converter.GenericConverter;
 import org.springframework.core.io.DescriptiveResource;
 import org.springframework.core.io.Resource;
+import org.springframework.core.test.fixtures.EnabledForTestGroups;
 import org.springframework.lang.Nullable;
-import org.springframework.tests.EnabledForTestGroups;
 import org.springframework.util.StopWatch;
 import org.springframework.util.StringUtils;
 
@@ -54,7 +54,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
-import static org.springframework.tests.TestGroup.PERFORMANCE;
+import static org.springframework.core.test.fixtures.TestGroup.PERFORMANCE;
 
 /**
  * Unit tests for {@link GenericConversionService}.

spring-core/src/test/java/org/springframework/core/env/MutablePropertySourcesTests.java

@@ -20,7 +20,7 @@ import java.util.Iterator;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.mock.env.MockPropertySource;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-core/src/test/java/org/springframework/core/env/PropertySourcesPropertyResolverTests.java

@@ -24,7 +24,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.core.convert.ConverterNotFoundException;
-import org.springframework.mock.env.MockPropertySource;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

spring-core/src/test/java/org/springframework/core/env/StandardEnvironmentTests.java

@@ -16,17 +16,16 @@
 
 package org.springframework.core.env;
 
-import java.lang.reflect.Field;
 import java.security.AccessControlException;
 import java.security.Permission;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
 import org.springframework.core.SpringProperties;
-import org.springframework.mock.env.MockPropertySource;
+import org.springframework.core.test.fixtures.env.EnvironmentTestUtils;
+import org.springframework.core.test.fixtures.env.MockPropertySource;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
@@ -465,8 +464,8 @@ public class StandardEnvironmentTests {
 
 	@Test
 	void getSystemEnvironment_withAndWithoutSecurityManager() {
-		getModifiableSystemEnvironment().put(ALLOWED_PROPERTY_NAME, ALLOWED_PROPERTY_VALUE);
-		getModifiableSystemEnvironment().put(DISALLOWED_PROPERTY_NAME, DISALLOWED_PROPERTY_VALUE);
+		EnvironmentTestUtils.getModifiableSystemEnvironment().put(ALLOWED_PROPERTY_NAME, ALLOWED_PROPERTY_VALUE);
+		EnvironmentTestUtils.getModifiableSystemEnvironment().put(DISALLOWED_PROPERTY_NAME, DISALLOWED_PROPERTY_VALUE);
 
 		{
 			Map<String, Object> systemEnvironment = environment.getSystemEnvironment();
@@ -500,68 +499,8 @@ public class StandardEnvironmentTests {
 		}
 
 		System.setSecurityManager(oldSecurityManager);
-		getModifiableSystemEnvironment().remove(ALLOWED_PROPERTY_NAME);
-		getModifiableSystemEnvironment().remove(DISALLOWED_PROPERTY_NAME);
-	}
-
-
-	@SuppressWarnings("unchecked")
-	public static Map<String, String> getModifiableSystemEnvironment() {
-		// for os x / linux
-		Class<?>[] classes = Collections.class.getDeclaredClasses();
-		Map<String, String> env = System.getenv();
-		for (Class<?> cl : classes) {
-			if ("java.util.Collections$UnmodifiableMap".equals(cl.getName())) {
-				try {
-					Field field = cl.getDeclaredField("m");
-					field.setAccessible(true);
-					Object obj = field.get(env);
-					if (obj != null && obj.getClass().getName().equals("java.lang.ProcessEnvironment$StringEnvironment")) {
-						return (Map<String, String>) obj;
-					}
-				}
-				catch (Exception ex) {
-					throw new RuntimeException(ex);
-				}
-			}
-		}
-
-		// for windows
-		Class<?> processEnvironmentClass;
-		try {
-			processEnvironmentClass = Class.forName("java.lang.ProcessEnvironment");
-		}
-		catch (Exception ex) {
-			throw new IllegalStateException(ex);
-		}
-
-		try {
-			Field theCaseInsensitiveEnvironmentField = processEnvironmentClass.getDeclaredField("theCaseInsensitiveEnvironment");
-			theCaseInsensitiveEnvironmentField.setAccessible(true);
-			Object obj = theCaseInsensitiveEnvironmentField.get(null);
-			return (Map<String, String>) obj;
-		}
-		catch (NoSuchFieldException ex) {
-			// do nothing
-		}
-		catch (Exception ex) {
-			throw new IllegalStateException(ex);
-		}
-
-		try {
-			Field theEnvironmentField = processEnvironmentClass.getDeclaredField("theEnvironment");
-			theEnvironmentField.setAccessible(true);
-			Object obj = theEnvironmentField.get(null);
-			return (Map<String, String>) obj;
-		}
-		catch (NoSuchFieldException ex) {
-			// do nothing
-		}
-		catch (Exception ex) {
-			throw new IllegalStateException(ex);
-		}
-
-		throw new IllegalStateException();
+		EnvironmentTestUtils.getModifiableSystemEnvironment().remove(ALLOWED_PROPERTY_NAME);
+		EnvironmentTestUtils.getModifiableSystemEnvironment().remove(DISALLOWED_PROPERTY_NAME);
 	}
 
 }

spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java

@@ -22,6 +22,8 @@ import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 
+import org.springframework.core.test.fixtures.io.buffer.AbstractDataBufferAllocatingTests;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;

spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferUtilsTests.java

@@ -45,7 +45,8 @@ import reactor.test.StepVerifier;
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
-import org.springframework.core.io.buffer.support.DataBufferTestUtils;
+import org.springframework.core.test.fixtures.io.buffer.AbstractDataBufferAllocatingTests;
+import org.springframework.core.test.fixtures.io.buffer.DataBufferTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;