Move DefaultLocaleExtension to junit-jupiter-api

Since the extension should only be active when the `@DefaultLocale`
annotation is used.

Author: marcphilipp

junit-jupiter-api/src/main/java/org/junit/jupiter/api/util/DefaultLocale.java

@@ -10,13 +10,16 @@
 
 package org.junit.jupiter.api.util;
 
+import static org.apiguardian.api.API.Status.STABLE;
+
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.apiguardian.api.API;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 /**
  * {@code @DefaultLocale} is a JUnit Jupiter extension to change the value
@@ -69,7 +72,8 @@
 @Target({ ElementType.METHOD, ElementType.TYPE })
 @Inherited
 @WritesDefaultLocale
-@API(status = API.Status.STABLE, since = "6.1")
+@API(status = STABLE, since = "6.1")
+@ExtendWith(DefaultLocaleExtension.class)
 public @interface DefaultLocale {
 
 	/**

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/extension/DefaultLocaleExtension.java renamed to junit-jupiter-api/src/main/java/org/junit/jupiter/api/util/DefaultLocaleExtension.java

@@ -8,7 +8,7 @@
  * https://www.eclipse.org/legal/epl-v20.html
  */
 
-package org.junit.jupiter.engine.extension;
+package org.junit.jupiter.api.util;
 
 import java.util.Locale;
 import java.util.Optional;
@@ -19,13 +19,13 @@
 import org.junit.jupiter.api.extension.ExtensionConfigurationException;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
-import org.junit.jupiter.api.util.DefaultLocale;
-import org.junit.jupiter.api.util.LocaleProvider;
 import org.junit.jupiter.api.util.LocaleProvider.NullLocaleProvider;
-import org.junit.jupiter.engine.support.JupiterLocaleUtils;
 import org.junit.platform.commons.support.AnnotationSupport;
 import org.junit.platform.commons.support.ReflectionSupport;
 
+/**
+ * @since 6.1
+ */
 class DefaultLocaleExtension implements BeforeAllCallback, BeforeEachCallback, AfterEachCallback {
 
 	private static final Namespace NAMESPACE = Namespace.create(DefaultLocaleExtension.class);

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/support/JupiterLocaleUtils.java renamed to junit-jupiter-api/src/main/java/org/junit/jupiter/api/util/JupiterLocaleUtils.java

@@ -8,17 +8,16 @@
  * https://www.eclipse.org/legal/epl-v20.html
  */
 
-package org.junit.jupiter.engine.support;
+package org.junit.jupiter.api.util;
 
 import java.util.Locale;
 
-import org.apiguardian.api.API;
-
 /**
  * Utility class to create {@code Locale}.
+ *
+ * @since 6.1
  */
-@API(status = API.Status.INTERNAL, since = "6.1")
-public class JupiterLocaleUtils {
+class JupiterLocaleUtils {
 
 	private JupiterLocaleUtils() {
 		// private constructor to prevent instantiation of utility class

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/extension/MutableExtensionRegistry.java

@@ -83,7 +83,6 @@ public static MutableExtensionRegistry createRegistryWithDefaultExtensions(Jupit
 		DEFAULT_STATELESS_EXTENSIONS.forEach(extensionRegistry::registerDefaultExtension);
 
 		extensionRegistry.registerDefaultExtension(new TempDirectory(configuration));
-		extensionRegistry.registerDefaultExtension(new DefaultLocaleExtension());
 		extensionRegistry.registerDefaultExtension(new DefaultTimeZoneExtension());
 
 		if (configuration.isExtensionAutoDetectionEnabled()) {

jupiter-tests/src/test/java/org/junit/jupiter/engine/extension/DefaultLocaleTests.java renamed to jupiter-tests/src/test/java/org/junit/jupiter/api/util/DefaultLocaleTests.java

@@ -8,7 +8,7 @@
  * https://www.eclipse.org/legal/epl-v20.html
  */
 
-package org.junit.jupiter.engine.extension;
+package org.junit.jupiter.api.util;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.testkit.JUnitJupiterTestKit.executeTestClass;
@@ -27,11 +27,6 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
 import org.junit.jupiter.api.extension.ExtensionConfigurationException;
-import org.junit.jupiter.api.util.DefaultLocale;
-import org.junit.jupiter.api.util.LocaleProvider;
-import org.junit.jupiter.api.util.ReadsDefaultLocale;
-import org.junit.jupiter.api.util.WritesDefaultLocale;
-import org.junit.jupiter.engine.support.JupiterLocaleUtils;
 import org.junit.jupiter.testkit.ExecutionResults;
 
 @DisplayName("DefaultLocale extension")