Introduce tests for PropertyDescriptorUtils with bounded generics

As a follow up to commit 4b07edbaeb, this commit introduces tests for
PropertyDescriptorUtils.determineBasicProperties() using types with
bounded generics.

Note, however, that the following test effectively fails, since
PropertyDescriptorUtils.determineBasicProperties() does not match the
behavior of java.beans.Introspector. Consequently, this test method
currently changes the expected write method type conditionally.

resolvePropertiesWithUnresolvedGenericsInSubclassWithOverloadedSetter()

See gh-36019

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

@@ -18,12 +18,14 @@ package org.springframework.beans;
 
 import java.beans.Introspector;
 import java.beans.PropertyDescriptor;
+import java.io.Serializable;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Stream;
 
 import org.junit.jupiter.api.Named;
+import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.Parameter;
 import org.junit.jupiter.params.ParameterizedClass;
@@ -58,58 +60,118 @@ class PropertyDescriptorUtilsPropertyResolutionTests {
 	PropertiesResolver resolver;
 
 
-	@Test
-	void determineBasicPropertiesWithUnresolvedGenericsInInterface() {
-		var pdMap = resolver.resolve(GenericService.class);
+	@Nested
+	class UnboundedGenericsTests {
 
-		assertThat(pdMap).containsOnlyKeys("id");
-		assertReadAndWriteMethodsForId(pdMap.get("id"), Object.class, Object.class);
-	}
+		@Test
+		void determineBasicPropertiesWithUnresolvedGenericsInInterface() {
+			var pdMap = resolver.resolve(GenericService.class);
 
-	@Test
-	void determineBasicPropertiesWithUnresolvedGenericsInSubInterface() {
-		// FYI: java.beans.Introspector does not resolve properties for sub-interfaces.
-		assumeThat(resolver).isNotInstanceOf(StandardPropertiesResolver.class);
+			assertThat(pdMap).containsOnlyKeys("id");
+			assertReadAndWriteMethodsForId(pdMap.get("id"), Object.class, Object.class);
+		}
 
-		var pdMap = resolver.resolve(SubGenericService.class);
+		@Test
+		void determineBasicPropertiesWithUnresolvedGenericsInSubInterface() {
+			// FYI: java.beans.Introspector does not resolve properties for sub-interfaces.
+			assumeThat(resolver).isNotInstanceOf(StandardPropertiesResolver.class);
 
-		assertThat(pdMap).containsOnlyKeys("id");
-		assertReadAndWriteMethodsForId(pdMap.get("id"), Object.class, Object.class);
-	}
+			var pdMap = resolver.resolve(SubGenericService.class);
 
-	@Test
-	void resolvePropertiesWithUnresolvedGenericsInClass() {
-		var pdMap = resolver.resolve(BaseService.class);
+			assertThat(pdMap).containsOnlyKeys("id");
+			assertReadAndWriteMethodsForId(pdMap.get("id"), Object.class, Object.class);
+		}
 
-		assertReadAndWriteMethodsForClassAndId(pdMap, Object.class, Object.class);
-	}
+		@Test
+		void resolvePropertiesWithUnresolvedGenericsInClass() {
+			var pdMap = resolver.resolve(BaseService.class);
 
-	@Test  // gh-36019
-	void resolvePropertiesInSubclassWithOverriddenGetterAndSetter() {
-		var pdMap = resolver.resolve(ServiceWithOverriddenGetterAndSetter.class);
+			assertReadAndWriteMethodsForClassAndId(pdMap, Object.class, Object.class);
+		}
 
-		assertReadAndWriteMethodsForClassAndId(pdMap, String.class, String.class);
-	}
+		@Test  // gh-36019
+		void resolvePropertiesInSubclassWithOverriddenGetterAndSetter() {
+			var pdMap = resolver.resolve(ServiceWithOverriddenGetterAndSetter.class);
 
-	@Test  // gh-36019
-	void resolvePropertiesWithUnresolvedGenericsInSubclassWithOverloadedSetter() {
-		var pdMap = resolver.resolve(ServiceWithOverloadedSetter.class);
+			assertReadAndWriteMethodsForClassAndId(pdMap, String.class, String.class);
+		}
 
-		assertReadAndWriteMethodsForClassAndId(pdMap, Object.class, Object.class);
-	}
+		@Test  // gh-36019
+		void resolvePropertiesWithUnresolvedGenericsInSubclassWithOverloadedSetter() {
+			var pdMap = resolver.resolve(ServiceWithOverloadedSetter.class);
 
-	@Test  // gh-36019
-	void resolvePropertiesWithPartiallyUnresolvedGenericsInSubclassWithOverriddenGetter() {
-		var pdMap = resolver.resolve(ServiceWithOverriddenGetter.class);
+			assertReadAndWriteMethodsForClassAndId(pdMap, Object.class, Object.class);
+		}
+
+		@Test  // gh-36019
+		void resolvePropertiesWithPartiallyUnresolvedGenericsInSubclassWithOverriddenGetter() {
+			var pdMap = resolver.resolve(ServiceWithOverriddenGetter.class);
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, String.class, Object.class);
+		}
+
+		@Test  // gh-36019
+		void resolvePropertiesWithPartiallyUnresolvedGenericsInSubclassWithOverriddenGetterAndOverloadedSetter() {
+			var pdMap = resolver.resolve(ServiceWithOverriddenGetterAndOverloadedSetter.class);
 
-		assertReadAndWriteMethodsForClassAndId(pdMap, String.class, Object.class);
+			assertReadAndWriteMethodsForClassAndId(pdMap, String.class, Object.class);
+		}
 	}
 
-	@Test  // gh-36019
-	void resolvePropertiesWithPartiallyUnresolvedGenericsInSubclassWithOverriddenGetterAndOverloadedSetter() {
-		var pdMap = resolver.resolve(ServiceWithOverriddenGetterAndOverloadedSetter.class);
+	@Nested
+	class BoundedGenericsTests {
+
+		@Test
+		void determineBasicPropertiesWithUnresolvedGenericsInInterface() {
+			var pdMap = resolver.resolve(Entity.class);
+
+			assertThat(pdMap).containsOnlyKeys("id");
+			assertReadAndWriteMethodsForId(pdMap.get("id"), Serializable.class, Serializable.class);
+		}
 
-		assertReadAndWriteMethodsForClassAndId(pdMap, String.class, Object.class);
+		@Test
+		void resolvePropertiesWithUnresolvedGenericsInClass() {
+			var pdMap = resolver.resolve(BaseEntity.class);
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, Number.class, Number.class);
+		}
+
+		@Test
+		void resolvePropertiesWithUnresolvedGenericsInSubclass() {
+			var pdMap = resolver.resolve(Person.class);
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, Number.class, Number.class);
+		}
+
+		@Test  // gh-36019
+		void resolvePropertiesWithUnresolvedGenericsInSubclassWithOverriddenGetter() {
+			var pdMap = resolver.resolve(PersonWithOverriddenGetter.class);
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, Long.class, Number.class);
+		}
+
+		@Test  // gh-36019
+		void resolvePropertiesWithUnresolvedGenericsInSubclassWithOverriddenSetter() {
+			var pdMap = resolver.resolve(PersonWithOverriddenSetter.class);
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, Number.class, Long.class);
+		}
+
+		@Test  // gh-36019
+		void resolvePropertiesWithUnresolvedGenericsInSubclassWithOverloadedSetter() {
+			var pdMap = resolver.resolve(PersonWithOverloadedSetter.class);
+
+			// TODO Determine if we want to align PropertyDescriptorUtils with java.beans.Introspector.
+			Class<?> writeType = Number.class;
+			if (resolver instanceof BasicPropertiesResolver) {
+				// PropertyDescriptorUtils currently incorrectly resolves setId(Integer)
+				// as the write method instead of setId(Number) (where Number is the
+				// unresolved generic for Long).
+				writeType = Integer.class;
+			}
+
+			assertReadAndWriteMethodsForClassAndId(pdMap, Number.class, writeType);
+		}
 	}
 
 
@@ -262,4 +324,62 @@ class PropertyDescriptorUtilsPropertyResolutionTests {
 		}
 	}
 
+	interface Entity<T extends Serializable> {
+
+		T getId();
+
+		void setId(T id);
+	}
+
+	abstract static class BaseEntity<T extends Number> implements Entity<T> {
+
+		private T id;
+
+		@Override
+		public T getId() {
+			return this.id;
+		}
+
+		@Override
+		public void setId(T id) {
+			this.id = id;
+		}
+	}
+
+	static class Person extends BaseEntity<Long> {
+	}
+
+	static class PersonWithOverriddenGetter extends BaseEntity<Long> {
+
+		/**
+		 * Overrides super implementation to ensure that the JavaBeans read method
+		 * is of type {@link Long}, while leaving the type for the write method
+		 * ({@link #setId}) set to {@link Number}.
+		 */
+		@Override
+		public Long getId() {
+			return super.getId();
+		}
+	}
+
+	static class PersonWithOverriddenSetter extends BaseEntity<Long> {
+
+		/**
+		 * Overrides super implementation to ensure that the JavaBeans write method
+		 * is of type {@link Long}, while leaving the type for the read method
+		 * ({@link #getId()}) set to {@link Number}.
+		 */
+		@Override
+		public void setId(Long id) {
+			super.setId(id);
+		}
+	}
+
+	static class PersonWithOverloadedSetter extends BaseEntity<Long> {
+
+		// Intentionally chose Integer, since it's a subtype of Long and Number.
+		public void setId(Integer id) {
+			setId(id.longValue());
+		}
+	}
 }