Support test annotations on interfaces

Prior to Java 8 it never really made much sense to author integration
tests using interfaces. Consequently, the Spring TestContext Framework
has never supported finding test-related annotations on interfaces in
its search algorithms.

However, Java 8's support for interface default methods introduces new
testing use cases for which it makes sense to declare test
configuration (e.g., @ContextConfiguration, etc.) on an interface
containing default methods instead of on an abstract base class.

This commit ensures that all non-repeatable, class-level test
annotations in the Spring TestContext Framework can now be declared on
test interfaces. The only test annotations that cannot be declared on
interfaces are therefore @SQL and @SqlGroup.

Issue: SPR-14184

Author: sbrannen

spring-context/src/test/java/org/springframework/tests/sample/beans/Employee.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -20,6 +20,13 @@ public class Employee extends TestBean {
 
 	private String co;
 
+	public Employee() {
+	}
+
+	public Employee(String name) {
+		super(name);
+	}
+
 	public String getCompany() {
 		return co;
 	}

spring-test/src/main/java/org/springframework/test/annotation/Commit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -18,6 +18,7 @@
 
 import java.lang.annotation.Documented;
 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;
@@ -51,6 +52,7 @@
 @Target({ElementType.TYPE, ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
+@Inherited
 @Rollback(false)
 public @interface Commit {
 }

spring-test/src/main/java/org/springframework/test/annotation/ProfileValueSourceConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -24,7 +24,7 @@
 import java.lang.annotation.Target;
 
 /**
- * <p>{@code ProfileValueSourceConfiguration} is a class-level annotation which
+ * {@code ProfileValueSourceConfiguration} is a class-level annotation which
  * is used to specify what type of {@link ProfileValueSource} to use when
  * retrieving <em>profile values</em> configured via the {@link IfProfileValue
  * &#064;IfProfileValue} annotation.
@@ -38,17 +38,15 @@
  * @see IfProfileValue
  * @see ProfileValueUtils
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface ProfileValueSourceConfiguration {
 
 	/**
-	 * <p>
 	 * The type of {@link ProfileValueSource} to use when retrieving
 	 * <em>profile values</em>.
-	 * </p>
 	 *
 	 * @see SystemProfileValueSource
 	 */

spring-test/src/main/java/org/springframework/test/annotation/Rollback.java

@@ -18,6 +18,7 @@
 
 import java.lang.annotation.Documented;
 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;
@@ -56,6 +57,7 @@
 @Target({ElementType.TYPE, ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
+@Inherited
 public @interface Rollback {
 
 	/**

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

@@ -43,10 +43,10 @@
  * @see org.springframework.context.ApplicationContext
  * @see org.springframework.context.annotation.Profile
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface ActiveProfiles {
 
 	/**

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

@@ -17,16 +17,15 @@
 package org.springframework.test.context;
 
 import java.lang.reflect.Constructor;
-import java.util.List;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.core.annotation.AnnotatedElementUtils;
-import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.MultiValueMap;
 
 /**
  * {@code BootstrapUtils} is a collection of utility methods to assist with
@@ -151,25 +150,26 @@ static TestContextBootstrapper resolveTestContextBootstrapper(BootstrapContext b
 	 * @since 4.3
 	 */
 	private static Class<?> resolveExplicitTestContextBootstrapper(Class<?> testClass) {
-		MultiValueMap<String, Object> attributesMultiMap =
-				AnnotatedElementUtils.getAllAnnotationAttributes(testClass, BootstrapWith.class.getName());
-		List<Object> values = (attributesMultiMap != null ? attributesMultiMap.get(AnnotationUtils.VALUE) : null);
-		if (values == null) {
+		Set<BootstrapWith> annotations = AnnotatedElementUtils.findAllMergedAnnotations(testClass, BootstrapWith.class);
+		if (annotations.size() < 1) {
 			return null;
 		}
-		if (values.size() != 1) {
-			throw new IllegalStateException(String.format("Configuration error: found multiple declarations of " +
-					"@BootstrapWith on test class [%s] with values %s", testClass.getName(), values));
+		if (annotations.size() > 1) {
+			throw new IllegalStateException(String.format(
+				"Configuration error: found multiple declarations of @BootstrapWith for test class [%s]: %s",
+				testClass.getName(), annotations));
 		}
-		return (Class<?>) values.get(0);
+		return annotations.iterator().next().value();
 	}
 
 	/**
 	 * @since 4.3
 	 */
 	private static Class<?> resolveDefaultTestContextBootstrapper(Class<?> testClass) throws Exception {
 		ClassLoader classLoader = BootstrapUtils.class.getClassLoader();
-		if (AnnotatedElementUtils.isAnnotated(testClass, WEB_APP_CONFIGURATION_ANNOTATION_CLASS_NAME)) {
+		AnnotationAttributes attributes = AnnotatedElementUtils.findMergedAnnotationAttributes(testClass,
+			WEB_APP_CONFIGURATION_ANNOTATION_CLASS_NAME, false, false);
+		if (attributes != null) {
 			return ClassUtils.forName(DEFAULT_WEB_TEST_CONTEXT_BOOTSTRAPPER_CLASS_NAME, classLoader);
 		}
 		return ClassUtils.forName(DEFAULT_TEST_CONTEXT_BOOTSTRAPPER_CLASS_NAME, classLoader);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -35,10 +35,10 @@
  * @see BootstrapContext
  * @see TestContextBootstrapper
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface BootstrapWith {
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -83,10 +83,10 @@
  * @see MergedContextConfiguration
  * @see org.springframework.context.ApplicationContext
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface ContextConfiguration {
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -139,10 +139,10 @@
  * @see ContextConfiguration
  * @see org.springframework.context.ApplicationContext
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface ContextHierarchy {
 
 	/**

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

@@ -42,10 +42,10 @@
  * @see TestContextManager
  * @see ContextConfiguration
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
 public @interface TestExecutionListeners {
 
 	/**