Provide first-class support for Bean Overrides with @⁠ContextHierarchy

This commit provides first-class support for Bean Overrides
(@⁠MockitoBean, @⁠MockitoSpyBean, @⁠TestBean, etc.) with
@⁠ContextHierarchy.

Specifically, bean overrides can now specify which ApplicationContext
they target within the context hierarchy by configuring the
`contextName` attribute in the annotation. The `contextName` must match
a corresponding `name` configured via @⁠ContextConfiguration.

For example, the following test class configures the name of the second
hierarchy level to be "child" and simultaneously specifies that the
ExampleService should be wrapped in a Mockito spy in the context named
"child". Consequently, Spring will only attempt to create the spy in
the "child" context and will not attempt to create the spy in the
parent context.

@ExtendWith(SpringExtension.class)
@ContextHierarchy({
    @ContextConfiguration(classes = Config1.class),
    @ContextConfiguration(classes = Config2.class, name = "child")
})
class MockitoSpyBeanContextHierarchyTests {

    @MockitoSpyBean(contextName = "child")
    ExampleService service;

    // ...
}

See spring-projectsgh-33293
See spring-projectsgh-34597
See spring-projectsgh-34726

Signed-off-by: Sam Brannen <104798+sbrannen@users.noreply.github.com>

Author: sbrannen

framework-docs/modules/ROOT/pages/testing/annotations/integration-spring/annotation-mockitobean.adoc

@@ -47,6 +47,21 @@ the same bean in several test classes, make sure to name the fields consistently
 creating unnecessary contexts.
 ====
 
+[WARNING]
+====
+Using `@MockitoBean` or `@MockitoSpyBean` in conjunction with `@ContextHierarchy` can
+lead to undesirable results since each `@MockitoBean` or `@MockitoSpyBean` will be
+applied to all context hierarchy levels by default. To ensure that a particular
+`@MockitoBean` or `@MockitoSpyBean` is applied to a single context hierarchy level, set
+the `contextName` attribute to match a configured `@ContextConfiguration` name – for
+example, `@MockitoBean(contextName = "app-config")` or
+`@MockitoSpyBean(contextName = "app-config")`.
+
+See
+xref:testing/testcontext-framework/ctx-management/hierarchies.adoc#testcontext-ctx-management-ctx-hierarchies-with-bean-overrides[context
+hierarchies with bean overrides] for further details and examples.
+====
+
 Each annotation also defines Mockito-specific attributes to fine-tune the mocking behavior.
 
 The `@MockitoBean` annotation uses the `REPLACE_OR_CREATE`

framework-docs/modules/ROOT/pages/testing/annotations/integration-spring/annotation-testbean.adoc

@@ -31,6 +31,19 @@ same bean in several tests, make sure to name the field consistently to avoid cr
 unnecessary contexts.
 ====
 
+[WARNING]
+====
+Using `@TestBean` in conjunction with `@ContextHierarchy` can lead to undesirable results
+since each `@TestBean` will be applied to all context hierarchy levels by default. To
+ensure that a particular `@TestBean` is applied to a single context hierarchy level, set
+the `contextName` attribute to match a configured `@ContextConfiguration` name – for
+example, `@TestBean(contextName = "app-config")`.
+
+See
+xref:testing/testcontext-framework/ctx-management/hierarchies.adoc#testcontext-ctx-management-ctx-hierarchies-with-bean-overrides[context
+hierarchies with bean overrides] for further details and examples.
+====
+
 [NOTE]
 ====
 There are no restrictions on the visibility of `@TestBean` fields or factory methods.

framework-docs/modules/ROOT/pages/testing/testcontext-framework/ctx-management/hierarchies.adoc

@@ -22,8 +22,19 @@ given level in the hierarchy, the configuration resource type (that is, XML conf
 files or component classes) must be consistent. Otherwise, it is perfectly acceptable to
 have different levels in a context hierarchy configured using different resource types.
 
-The remaining JUnit Jupiter based examples in this section show common configuration
-scenarios for integration tests that require the use of context hierarchies.
+[NOTE]
+====
+If you use `@DirtiesContext` in a test whose context is configured as part of a context
+hierarchy, you can use the `hierarchyMode` flag to control how the context cache is
+cleared.
+
+For further details, see the discussion of `@DirtiesContext` in
+xref:testing/annotations/integration-spring/annotation-dirtiescontext.adoc[Spring Testing Annotations]
+and the {spring-framework-api}/test/annotation/DirtiesContext.html[`@DirtiesContext`] javadoc.
+====
+
+The JUnit Jupiter based examples in this section show common configuration scenarios for
+integration tests that require the use of context hierarchies.
 
 **Single test class with context hierarchy**
 --
@@ -229,12 +240,95 @@ Kotlin::
 	class ExtendedTests : BaseTests() {}
 ----
 ======
+--
 
-.Dirtying a context within a context hierarchy
-NOTE: If you use `@DirtiesContext` in a test whose context is configured as part of a
-context hierarchy, you can use the `hierarchyMode` flag to control how the context cache
-is cleared. For further details, see the discussion of `@DirtiesContext` in
-xref:testing/annotations/integration-spring/annotation-dirtiescontext.adoc[Spring Testing Annotations] and the
-{spring-framework-api}/test/annotation/DirtiesContext.html[`@DirtiesContext`] javadoc.
+[[testcontext-ctx-management-ctx-hierarchies-with-bean-overrides]]
+**Context hierarchies with bean overrides**
 --
+When `@ContextHierarchy` is used in conjunction with
+xref:testing/testcontext-framework/bean-overriding.adoc[bean overrides] such as
+`@TestBean`, `@MockitoBean`, or `@MockitoSpyBean`, it may be desirable or necessary to
+have the override applied to a single level in the context hierarchy. To achieve that,
+the bean override must specify a context name that matches a name configured via the
+`name` attribute in `@ContextConfiguration`.
+
+The following test class configures the name of the second hierarchy level to be
+`"user-config"` and simultaneously specifies that the `UserService` should be wrapped in
+a Mockito spy in the context named `"user-config"`. Consequently, Spring will only
+attempt to create the spy in the `"user-config"` context and will not attempt to create
+the spy in the parent context.
+
+[tabs]
+======
+Java::
++
+[source,java,indent=0,subs="verbatim,quotes"]
+----
+@ExtendWith(SpringExtension.class)
+@ContextHierarchy({
+	@ContextConfiguration(classes = AppConfig.class),
+	@ContextConfiguration(classes = UserConfig.class, name = "user-config")
+})
+class IntegrationTests {
+
+	@MockitoSpyBean(contextName = "user-config")
+	UserService userService;
+
+	// ...
+}
+----
+
+Kotlin::
++
+[source,kotlin,indent=0,subs="verbatim,quotes"]
+----
+XXX
+----
+======
 
+When applying bean overrides in different levels of the context hierarchy, you may need
+to have all of the bean override instances injected into the test class in order to
+interact with them — for example, to configure stubbing for mocks. However, `@Autowired`
+will always inject a matching bean found in the lowest level of the context hierarchy.
+Thus, to inject bean override instances from specific levels in the context hierarchy,
+you need to annotate fields with appropriate bean override annotations and configure the
+name of the context level.
+
+The following test class configures the names of the hierarchy levels to be `"parent"`
+and `"child"`. It also declares two `PropertyService` fields that are configured to
+create or replace `PropertyService` beans with Mockito mocks in the respective contexts,
+named `"parent"` and `"child"`. Consequently, the mock from the `"parent"` context will
+be injected into the `propertyServiceInParent` field, and the mock from the `"child"`
+context will be injected into the `propertyServiceInChild` field.
+
+[tabs]
+======
+Java::
++
+[source,java,indent=0,subs="verbatim,quotes"]
+----
+@ExtendWith(SpringExtension.class)
+@ContextHierarchy({
+	@ContextConfiguration(classes = ParentConfig.class, name = "parent"),
+	@ContextConfiguration(classes = ChildConfig.class, name = "child")
+})
+class IntegrationTests {
+
+	@MockitoBean(contextName = "parent")
+	PropertyService propertyServiceInParent;
+
+	@MockitoBean(contextName = "child")
+	PropertyService propertyServiceInChild;
+
+	// ...
+}
+----
+
+Kotlin::
++
+[source,kotlin,indent=0,subs="verbatim,quotes"]
+----
+XXX
+----
+======
+--

spring-test/src/main/java/org/springframework/test/context/ContextConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -292,13 +292,18 @@
 	 * <p>If not specified the name will be inferred based on the numerical level
 	 * within all declared contexts within the hierarchy.
 	 * <p>This attribute is only applicable when used within a test class hierarchy
-	 * or enclosing class hierarchy that is configured using
-	 * {@code @ContextHierarchy}, in which case the name can be used for
-	 * <em>merging</em> or <em>overriding</em> this configuration with configuration
-	 * of the same name in hierarchy levels defined in superclasses or enclosing
-	 * classes. See the Javadoc for {@link ContextHierarchy @ContextHierarchy} for
-	 * details.
+	 * or enclosing class hierarchy that is configured using {@code @ContextHierarchy},
+	 * in which case the name can be used for <em>merging</em> or <em>overriding</em>
+	 * this configuration with configuration of the same name in hierarchy levels
+	 * defined in superclasses or enclosing classes. As of Spring Framework 6.2.6,
+	 * the name can also be used to identify the configuration in which a
+	 * <em>Bean Override</em> should be applied &mdash; for example,
+	 * {@code @MockitoBean(contextName = "child")}. See the Javadoc for
+	 * {@link ContextHierarchy @ContextHierarchy} for details.
 	 * @since 3.2.2
+	 * @see org.springframework.test.context.bean.override.mockito.MockitoBean#contextName @MockitoBean(contextName = ...)
+	 * @see org.springframework.test.context.bean.override.mockito.MockitoSpyBean#contextName @MockitoSpyBean(contextName = ...)
+	 * @see org.springframework.test.context.bean.override.convention.TestBean#contextName @TestBean(contextName = ...)
 	 */
 	String name() default "";
 

spring-test/src/main/java/org/springframework/test/context/ContextHierarchy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -29,10 +29,12 @@
  * ApplicationContexts} for integration tests.
  *
  * <h3>Examples</h3>
+ *
  * <p>The following JUnit-based examples demonstrate common configuration
  * scenarios for integration tests that require the use of context hierarchies.
  *
  * <h4>Single Test Class with Context Hierarchy</h4>
+ *
  * <p>{@code ControllerIntegrationTests} represents a typical integration testing
  * scenario for a Spring MVC web application by declaring a context hierarchy
  * consisting of two levels, one for the <em>root</em> {@code WebApplicationContext}
@@ -57,6 +59,7 @@
  * }</pre>
  *
  * <h4>Class Hierarchy with Implicit Parent Context</h4>
+ *
  * <p>The following test classes define a context hierarchy within a test class
  * hierarchy. {@code AbstractWebTests} declares the configuration for a root
  * {@code WebApplicationContext} in a Spring-powered web application. Note,
@@ -83,12 +86,13 @@
  * public class RestWebServiceTests extends AbstractWebTests {}</pre>
  *
  * <h4>Class Hierarchy with Merged Context Hierarchy Configuration</h4>
+ *
  * <p>The following classes demonstrate the use of <em>named</em> hierarchy levels
  * in order to <em>merge</em> the configuration for specific levels in a context
- * hierarchy. {@code BaseTests} defines two levels in the hierarchy, {@code parent}
- * and {@code child}. {@code ExtendedTests} extends {@code BaseTests} and instructs
+ * hierarchy. {@code BaseTests} defines two levels in the hierarchy, {@code "parent"}
+ * and {@code "child"}. {@code ExtendedTests} extends {@code BaseTests} and instructs
  * the Spring TestContext Framework to merge the context configuration for the
- * {@code child} hierarchy level, simply by ensuring that the names declared via
+ * {@code "child"} hierarchy level, simply by ensuring that the names declared via
  * {@link ContextConfiguration#name} are both {@code "child"}. The result is that
  * three application contexts will be loaded: one for {@code "/app-config.xml"},
  * one for {@code "/user-config.xml"}, and one for <code>{"/user-config.xml",
@@ -111,6 +115,7 @@
  * public class ExtendedTests extends BaseTests {}</pre>
  *
  * <h4>Class Hierarchy with Overridden Context Hierarchy Configuration</h4>
+ *
  * <p>In contrast to the previous example, this example demonstrates how to
  * <em>override</em> the configuration for a given named level in a context hierarchy
  * by setting the {@link ContextConfiguration#inheritLocations} flag to {@code false}.
@@ -131,6 +136,72 @@
  * )
  * public class ExtendedTests extends BaseTests {}</pre>
  *
+ * <h4>Context Hierarchies with Bean Overrides</h4>
+ *
+ * <p>When {@code @ContextHierarchy} is used in conjunction with bean overrides such as
+ * {@link org.springframework.test.context.bean.override.convention.TestBean @TestBean},
+ * {@link org.springframework.test.context.bean.override.mockito.MockitoBean @MockitoBean}, or
+ * {@link org.springframework.test.context.bean.override.mockito.MockitoSpyBean @MockitoSpyBean},
+ * it may be desirable or necessary to have the override applied to a single level
+ * in the context hierarchy. To achieve that, the bean override must specify a
+ * context name that matches a name configured via {@link ContextConfiguration#name}.
+ *
+ * <p>The following test class configures the name of the second hierarchy level to be
+ * {@code "user-config"} and simultaneously specifies that the {@code UserService} should
+ * be wrapped in a Mockito spy in the context named {@code "user-config"}. Consequently,
+ * Spring will only attempt to create the spy in the {@code "user-config"} context and will
+ * not attempt to create the spy in the parent context.
+ *
+ * <pre class="code">
+ * &#064;ExtendWith(SpringExtension.class)
+ * &#064;ContextHierarchy({
+ *     &#064;ContextConfiguration(classes = AppConfig.class),
+ *     &#064;ContextConfiguration(classes = UserConfig.class, name = "user-config")
+ * })
+ * class IntegrationTests {
+ *
+ *     &#064;MockitoSpyBean(contextName = "user-config")
+ *     UserService userService;
+ *
+ *     // ...
+ * }</pre>
+ *
+ * <p>When applying bean overrides in different levels of the context hierarchy, you may
+ * need to have all of the bean override instances injected into the test class in order
+ * to interact with them &mdash; for example, to configure stubbing for mocks. However,
+ * {@link org.springframework.beans.factory.annotation.Autowired @Autowired} will always
+ * inject a matching bean found in the lowest level of the context hierarchy. Thus, to
+ * inject bean override instances from specific levels in the context hierarchy, you need
+ * to annotate fields with appropriate bean override annotations and configure the name
+ * of the context level.
+ *
+ * <p>The following test class configures the names of the hierarchy levels to be
+ * {@code "parent"} and {@code "child"}. It also declares two {@code PropertyService}
+ * fields that are configured to create or replace {@code PropertyService} beans with
+ * Mockito mocks in the respective contexts, named {@code "parent"} and {@code "child"}.
+ * Consequently, the mock from the {@code "parent"} context will be injected into the
+ * {@code propertyServiceInParent} field, and the mock from the {@code "child"} context
+ * will be injected into the {@code propertyServiceInChild} field.
+ *
+ * <pre class="code">
+ * &#064;ExtendWith(SpringExtension.class)
+ * &#064;ContextHierarchy({
+ *     &#064;ContextConfiguration(classes = ParentConfig.class, name = "parent"),
+ *     &#064;ContextConfiguration(classes = ChildConfig.class, name = "child")
+ * })
+ * class IntegrationTests {
+ *
+ *     &#064;MockitoBean(contextName = "parent")
+ *     PropertyService propertyServiceInParent;
+ *
+ *     &#064;MockitoBean(contextName = "child")
+ *     PropertyService propertyServiceInChild;
+ *
+ *     // ...
+ * }</pre>
+ *
+ * <h4>Miscellaneous</h4>
+ *
  * <p>This annotation may be used as a <em>meta-annotation</em> to create custom
  * <em>composed annotations</em>.
  *

spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideContextCustomizerFactory.java

@@ -42,19 +42,25 @@ class BeanOverrideContextCustomizerFactory implements ContextCustomizerFactory {
 	public BeanOverrideContextCustomizer createContextCustomizer(Class<?> testClass,
 			List<ContextConfigurationAttributes> configAttributes) {
 
+		// Base the context name on the "closest" @ContextConfiguration declaration
+		// within the type and enclosing class hierarchies of the test class.
+		String contextName = configAttributes.get(0).getName();
 		Set<BeanOverrideHandler> handlers = new LinkedHashSet<>();
-		findBeanOverrideHandlers(testClass, handlers);
+		findBeanOverrideHandlers(testClass, contextName, handlers);
 		if (handlers.isEmpty()) {
 			return null;
 		}
 		return new BeanOverrideContextCustomizer(handlers);
 	}
 
-	private void findBeanOverrideHandlers(Class<?> testClass, Set<BeanOverrideHandler> handlers) {
-		BeanOverrideHandler.findAllHandlers(testClass).forEach(handler ->
-				Assert.state(handlers.add(handler), () ->
-						"Duplicate BeanOverrideHandler discovered in test class %s: %s"
-							.formatted(testClass.getName(), handler)));
+	private void findBeanOverrideHandlers(Class<?> testClass, @Nullable String contextName, Set<BeanOverrideHandler> handlers) {
+		BeanOverrideHandler.findAllHandlers(testClass).stream()
+				// If a handler does not specify a context name, it always gets applied.
+				// Otherwise, the handler's context name must match the current context name.
+				.filter(handler -> handler.getContextName().isEmpty() || handler.getContextName().equals(contextName))
+				.forEach(handler -> Assert.state(handlers.add(handler),
+						() -> "Duplicate BeanOverrideHandler discovered in test class %s: %s"
+								.formatted(testClass.getName(), handler)));
 	}
 
 }