Allow @RegisterExtension/@ExtendWith fields to be sorted relative to each other

Prior to this commit, @ExtendWith fields and @RegisterExtension fields
were sorted using @order, but extensions registered via @ExtendWith fields
were always registered first (before extensions registered via
@RegisterExtension fields).

This commit ensures that @RegisterExtension fields and @ExtendWith fields
are sorted via @order relative to each other.

See #864, #2680

Author: sbrannen

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ExtensionUtils.java

@@ -21,7 +21,6 @@
 import java.lang.reflect.AnnotatedElement;
 import java.lang.reflect.Executable;
 import java.lang.reflect.Field;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
@@ -93,28 +92,24 @@ static void registerExtensionsFromFields(ExtensionRegistrar registrar, Class<?>
 
 		Predicate<Field> predicate = (instance == null ? ReflectionUtils::isStatic : ReflectionUtils::isNotStatic);
 
-		// Ensure that the list is modifiable, since findFields() returns an unmodifiable list.
-		List<Field> fields = new ArrayList<>(findFields(clazz, predicate, TOP_DOWN));
-
-		// Sort fields based on @Order.
-		fields.sort(orderComparator);
-
-		// @formatter:off
-		fields.stream()
-			.flatMap(ExtensionUtils::streamExtensionTypes)
-			.forEach(registrar::registerExtension);
-
-		fields.stream()
-			.filter(field -> isAnnotated(field, RegisterExtension.class))
-			.forEach(field -> {
-				tryToReadFieldValue(field, instance).ifSuccess(value -> {
-					Preconditions.condition(value instanceof Extension, () -> String.format(
-						"Failed to register extension via @RegisterExtension field [%s]: field value's type [%s] must implement an [%s] API.",
-						field, (value != null ? value.getClass().getName() : null), Extension.class.getName()));
-					registrar.registerExtension((Extension) value, field);
+		findFields(clazz, predicate, TOP_DOWN).stream()//
+				.sorted(orderComparator)//
+				.forEach(field -> {
+					List<ExtendWith> extendWithAnnotations = findRepeatableAnnotations(field, ExtendWith.class);
+					boolean isExtendWithPresent = !extendWithAnnotations.isEmpty();
+					boolean isRegisterExtensionPresent = isAnnotated(field, RegisterExtension.class);
+					if (isExtendWithPresent) {
+						streamExtensionTypes(extendWithAnnotations).forEach(registrar::registerExtension);
+					}
+					if (isRegisterExtensionPresent) {
+						tryToReadFieldValue(field, instance).ifSuccess(value -> {
+							Preconditions.condition(value instanceof Extension, () -> String.format(
+								"Failed to register extension via @RegisterExtension field [%s]: field value's type [%s] must implement an [%s] API.",
+								field, (value != null ? value.getClass().getName() : null), Extension.class.getName()));
+							registrar.registerExtension((Extension) value, field);
+						});
+					}
 				});
-			});
-		// @formatter:on
 	}
 
 	/**

junit-jupiter-engine/src/test/java/org/junit/jupiter/engine/extension/ExtensionRegistrationViaParametersAndFieldsTests.java

@@ -139,39 +139,39 @@ void registrationOrder(LogRecordListener listener) {
 		assertOneTestSucceeded(AllInOneWithTestInstancePerMethodTestCase.class);
 		assertThat(getRegisteredLocalExtensions(listener))//
 				.containsExactly(//
-					"StaticField1", // @ExtendWith on static field
+					"ClassLevelExtension2", // @RegisterExtension on static field
 					"StaticField2", // @ExtendWith on static field
 					"ClassLevelExtension1", // @RegisterExtension on static field
-					"ClassLevelExtension2", // @RegisterExtension on static field
+					"StaticField1", // @ExtendWith on static field
 					"ConstructorParameter", // @ExtendWith on parameter in constructor
 					"BeforeAllParameter", // @ExtendWith on parameter in static @BeforeAll method
 					"BeforeEachParameter", // @ExtendWith on parameter in @BeforeEach method
 					"AfterEachParameter", // @ExtendWith on parameter in @AfterEach method
 					"AfterAllParameter", // @ExtendWith on parameter in static @AfterAll method
 					"TestParameter", // @ExtendWith on parameter in @Test method
-					"InstanceField1", // @ExtendWith on instance field
-					"InstanceField2", // @ExtendWith on instance field
 					"InstanceLevelExtension1", // @RegisterExtension on instance field
-					"InstanceLevelExtension2"// @RegisterExtension on instance field
+					"InstanceField1", // @ExtendWith on instance field
+					"InstanceLevelExtension2", // @RegisterExtension on instance field
+					"InstanceField2" // @ExtendWith on instance field
 				);
 
 		listener.clear();
 		assertOneTestSucceeded(AllInOneWithTestInstancePerClassTestCase.class);
 		assertThat(getRegisteredLocalExtensions(listener))//
 				.containsExactly(//
-					"StaticField1", // @ExtendWith on static field
+					"ClassLevelExtension2", // @RegisterExtension on static field
 					"StaticField2", // @ExtendWith on static field
 					"ClassLevelExtension1", // @RegisterExtension on static field
-					"ClassLevelExtension2", // @RegisterExtension on static field
+					"StaticField1", // @ExtendWith on static field
 					"ConstructorParameter", // @ExtendWith on parameter in constructor
 					"BeforeAllParameter", // @ExtendWith on parameter in static @BeforeAll method
 					"BeforeEachParameter", // @ExtendWith on parameter in @BeforeEach method
 					"AfterEachParameter", // @ExtendWith on parameter in @AfterEach method
 					"AfterAllParameter", // @ExtendWith on parameter in static @AfterAll method
-					"InstanceField1", // @ExtendWith on instance field
-					"InstanceField2", // @ExtendWith on instance field
 					"InstanceLevelExtension1", // @RegisterExtension on instance field
+					"InstanceField1", // @ExtendWith on instance field
 					"InstanceLevelExtension2", // @RegisterExtension on instance field
+					"InstanceField2", // @ExtendWith on instance field
 					"TestParameter" // @ExtendWith on parameter in @Test method
 				);
 	}
@@ -603,33 +603,35 @@ void test() {
 	static class AllInOneWithTestInstancePerMethodTestCase {
 
 		@StaticField1
+		@Order(Integer.MAX_VALUE)
 		static String staticField1;
 
 		@StaticField2
 		@ExtendWith(StaticField2.Extension.class)
+		@Order(3)
 		static String staticField2;
 
+		@RegisterExtension
+		private static Extension classLevelExtension1 = new ClassLevelExtension1();
+
+		@RegisterExtension
+		@Order(1)
+		static Extension classLevelExtension2 = new ClassLevelExtension2();
+
 		@InstanceField1
+		@Order(2)
 		String instanceField1;
 
 		@InstanceField2
 		@ExtendWith(InstanceField2.Extension.class)
 		String instanceField2;
 
-		@RegisterExtension
-		@Order(1)
-		private static Extension classLevelExtension1 = new ClassLevelExtension1();
-
-		@RegisterExtension
-		@Order(2)
-		static Extension classLevelExtension2 = new ClassLevelExtension2();
-
 		@RegisterExtension
 		@Order(1)
 		private Extension instanceLevelExtension1 = new InstanceLevelExtension1();
 
 		@RegisterExtension
-		@Order(2)
+		@Order(3)
 		Extension instanceLevelExtension2 = new InstanceLevelExtension2();
 
 		AllInOneWithTestInstancePerMethodTestCase(@ConstructorParameter String text) {