[SPR-8386] AbstractContextLoader now adheres to the SmartContextLoader contract by verifying the existence of generated default resource locations.

org.springframework.test/src/main/java/org/springframework/test/context/support/AbstractContextLoader.java

@@ -16,7 +16,10 @@
 
 package org.springframework.test.context.support;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.context.ApplicationContext;
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.support.ResourcePatternUtils;
 import org.springframework.test.context.ContextConfigurationAttributes;
 import org.springframework.test.context.ContextLoader;
@@ -29,9 +32,16 @@ import org.springframework.util.StringUtils;
 
 /**
  * Abstract application context loader, which provides a basis for all concrete
- * implementations of the {@link ContextLoader} strategy. Provides a
+ * implementations of the {@link ContextLoader} SPI. Provides a
  * <em>Template Method</em> based approach for {@link #processLocations processing}
- * locations.
+ * resource locations.
+ * 
+ * <p>As of Spring 3.1, <code>AbstractContextLoader</code> also provides a basis
+ * for all concrete implementations of the {@link SmartContextLoader} SPI. For
+ * backwards compatibility with the {@code ContextLoader} SPI, 
+ * {@link #processContextConfiguration()} delegates to
+ * {@link #processLocations()}, and {@link #generatesDefaults()} delegates to
+ * {@link #isGenerateDefaultLocations()}. 
  *
  * @author Sam Brannen
  * @author Juergen Hoeller
@@ -41,14 +51,18 @@ import org.springframework.util.StringUtils;
  */
 public abstract class AbstractContextLoader implements SmartContextLoader {
 
+	private static final Log logger = LogFactory.getLog(AbstractContextLoader.class);
+
+	private static final String[] EMPTY_STRING_ARRAY = new String[] {};
 	private static final String SLASH = "/";
 
 
 	// --- SmartContextLoader -----------------------------------------------
 
 	/**
-	 * TODO Document generatesDefaults() implementation.
-	 *
+	 * For backwards compatibility with the {@link ContextLoader} SPI, the
+	 * default implementation simply delegates to
+	 * {@link #isGenerateDefaultLocations()}.
 	 * @see org.springframework.test.context.SmartContextLoader#generatesDefaults()
 	 * @see #isGenerateDefaultLocations()
 	 */
@@ -57,14 +71,22 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 	}
 
 	/**
-	 * TODO Document processContextConfiguration() implementation.
-	 * 
-	 * @see #processLocations(Class, String...)
+	 * For backwards compatibility with the {@link ContextLoader} SPI, the
+	 * default implementation simply delegates to {@link #processLocations()},
+	 * passing it the {@link ContextConfigurationAttributes#getDeclaringClass()
+	 * declaring class} and {@link ContextConfigurationAttributes#getLocations()
+	 * resource locations} retrieved from the supplied
+	 * {@link ContextConfigurationAttributes configuration attributes}. The
+	 * processed locations are then
+	 * {@link ContextConfigurationAttributes#setLocations(String[]) set} in
+	 * the supplied configuration attributes.
+	 * <p>Can be overridden in subclasses &mdash; for example, to process
+	 * configuration classes instead of resource locations.
+	 * @see #processLocations()
 	 */
 	public void processContextConfiguration(ContextConfigurationAttributes configAttributes) {
 		String[] processedLocations = processLocations(configAttributes.getDeclaringClass(),
 			configAttributes.getLocations());
-
 		configAttributes.setLocations(processedLocations);
 	}
 
@@ -72,7 +94,7 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 
 	/**
 	 * If the supplied <code>locations</code> are <code>null</code> or
-	 * <em>empty</em> and {@link #isGenerateDefaultLocations()} is
+	 * <em>empty</em> and {@link #isGenerateDefaultLocations()} returns
 	 * <code>true</code>, default locations will be
 	 * {@link #generateDefaultLocations(Class) generated} for the specified
 	 * {@link Class class} and the configured
@@ -83,10 +105,12 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 	 * used when generating default locations
 	 * @param locations the unmodified locations to use for loading the
 	 * application context (can be <code>null</code> or empty)
-	 * @return an array of application context resource locations
-	 * @see #generateDefaultLocations
-	 * @see #modifyLocations
-	 * @see org.springframework.test.context.ContextLoader#processLocations
+	 * @return a processed array of application context resource locations
+	 * @see #isGenerateDefaultLocations()
+	 * @see #generateDefaultLocations()
+	 * @see #modifyLocations()
+	 * @see org.springframework.test.context.ContextLoader#processLocations()
+	 * @see #processContextConfiguration()
 	 */
 	public final String[] processLocations(Class<?> clazz, String... locations) {
 		return (ObjectUtils.isEmpty(locations) && isGenerateDefaultLocations()) ? generateDefaultLocations(clazz)
@@ -101,6 +125,11 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 	 * &quot;classpath:/com/example/MyTest<code>&lt;suffix&gt;</code>&quot;,
 	 * where <code>&lt;suffix&gt;</code> is the value of the
 	 * {@link #getResourceSuffix() resource suffix} string.
+	 * <p>As of Spring 3.1, the implementation of this method adheres to the
+	 * contract defined in the {@link SmartContextLoader} SPI. Specifically, 
+	 * this method will <em>preemptively</em> verify that the generated default
+	 * location actually exists. If it does not exist, this method will log a
+	 * warning and return an empty array.
 	 * <p>Subclasses can override this method to implement a different
 	 * <em>default location generation</em> strategy.
 	 * @param clazz the class for which the default locations are to be generated
@@ -111,12 +140,17 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 		Assert.notNull(clazz, "Class must not be null");
 		String suffix = getResourceSuffix();
 		Assert.hasText(suffix, "Resource suffix must not be empty");
+		String resourcePath = SLASH + ClassUtils.convertClassNameToResourcePath(clazz.getName()) + suffix;
+
+		if (!new ClassPathResource(resourcePath, clazz).exists()) {
+			logger.warn(String.format(
+				"Cannot generate default resource location for test class [%s]: classpath resource [%s] does not exist.",
+				clazz.getName(), resourcePath));
+			return EMPTY_STRING_ARRAY;
+		}
 
-		// TODO Adhere to SmartContextLoader contract: verify existence of
-		// default and return an empty array if non-existent, in which case a
-		// warning should be logged as well.
-		return new String[] { ResourceUtils.CLASSPATH_URL_PREFIX + SLASH
-				+ ClassUtils.convertClassNameToResourcePath(clazz.getName()) + suffix };
+		// else
+		return new String[] { ResourceUtils.CLASSPATH_URL_PREFIX + resourcePath };
 	}
 
 	/**
@@ -157,8 +191,7 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 	/**
 	 * Determine whether or not <em>default</em> resource locations should be
 	 * generated if the <code>locations</code> provided to
-	 * {@link #processLocations(Class,String...) processLocations()} are
-	 * <code>null</code> or empty.
+	 * {@link #processLocations()} are <code>null</code> or empty.
 	 * <p>Can be overridden by subclasses to change the default behavior.
 	 * @return always <code>true</code> by default
 	 */
@@ -171,7 +204,7 @@ public abstract class AbstractContextLoader implements SmartContextLoader {
 	 * locations when generating default locations.
 	 * <p>Must be implemented by subclasses.
 	 * @return the resource suffix; should not be <code>null</code> or empty
-	 * @see #generateDefaultLocations(Class)
+	 * @see #generateDefaultLocations()
 	 */
 	protected abstract String getResourceSuffix();
 

org.springframework.test/src/main/java/org/springframework/test/context/support/AnnotationConfigContextLoader.java

@@ -63,7 +63,7 @@ public class AnnotationConfigContextLoader extends AbstractGenericContextLoader
 	/**
 	 * TODO Document overridden processContextConfiguration().
 	 *
-	 * @see org.springframework.test.context.SmartContextLoader#processContextConfiguration
+	 * @see org.springframework.test.context.SmartContextLoader#processContextConfiguration()
 	 * @see #generatesDefaults
 	 * @see #generateDefaultConfigurationClasses
 	 */
@@ -102,7 +102,20 @@ public class AnnotationConfigContextLoader extends AbstractGenericContextLoader
 	}
 
 	/**
-	 * TODO Document generateDefaultConfigurationClasses().
+	 * TODO Complete JavaDoc for generateDefaultConfigurationClasses().
+	 * 
+	 * <p>The implementation of this method adheres to the contract defined in the
+	 * {@link org.springframework.test.context.SmartContextLoader SmartContextLoader}
+	 * SPI. Specifically, this method will <em>preemptively</em> verify that the
+	 * generated default configuration classes exist <b>and</b> that such classes
+	 * comply with the constraints required of {@link Configuration @Configuration}
+	 * class implementations. If a candidate configuration class does meet these
+	 * requirements, this method will log a warning and potentially return an empty
+	 * array.
+	 *
+	 * @param declaringClass the test class that declared
+	 * {@link org.springframework.test.context.ContextConfiguration @ContextConfiguration}
+	 * @return
 	 */
 	protected Class<?>[] generateDefaultConfigurationClasses(Class<?> declaringClass) {
 		Assert.notNull(declaringClass, "Declaring class must not be null");

org.springframework.test/src/test/java/org/springframework/test/context/ContextLoaderUtilsTests$BareAnnotations-context.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
+
+	<!-- intentionally empty: only needed so that the ContextLoader can find this file -->
+
+</beans>

org.springframework.test/src/test/java/org/springframework/test/context/support/GenericXmlContextLoaderResourceLocationsTests$1ClasspathExistentDefaultLocationsTestCase-context.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
+
+	<!-- intentionally empty: only needed so that the ContextLoader can find this file -->
+
+</beans>

org.springframework.test/src/test/java/org/springframework/test/context/support/GenericXmlContextLoaderResourceLocationsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2007 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -27,7 +27,6 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 import org.junit.runners.Parameterized.Parameters;
-
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.ContextLoader;
@@ -63,35 +62,41 @@ public class GenericXmlContextLoaderResourceLocationsTests {
 	@Parameters
 	public static Collection<Object[]> contextConfigurationLocationsData() {
 		@ContextConfiguration
-		class ClasspathDefaultLocationsTestCase {
+		class ClasspathNonExistentDefaultLocationsTestCase {
+		}
+
+		@ContextConfiguration
+		class ClasspathExistentDefaultLocationsTestCase {
 		}
-	
-		@ContextConfiguration(locations = { "context1.xml", "context2.xml" })
+
+		@ContextConfiguration({ "context1.xml", "context2.xml" })
 		class ImplicitClasspathLocationsTestCase {
 		}
-	
-		@ContextConfiguration(locations = { "classpath:context.xml" })
+
+		@ContextConfiguration("classpath:context.xml")
 		class ExplicitClasspathLocationsTestCase {
 		}
-	
-		@ContextConfiguration(locations = { "file:/testing/directory/context.xml" })
+
+		@ContextConfiguration("file:/testing/directory/context.xml")
 		class ExplicitFileLocationsTestCase {
 		}
-	
-		@ContextConfiguration(locations = { "http://example.com/context.xml" })
+
+		@ContextConfiguration("http://example.com/context.xml")
 		class ExplicitUrlLocationsTestCase {
 		}
-	
-		@ContextConfiguration(locations = { "context1.xml", "classpath:context2.xml", "/context3.xml",
+
+		@ContextConfiguration({ "context1.xml", "classpath:context2.xml", "/context3.xml",
 			"file:/testing/directory/context.xml", "http://example.com/context.xml" })
 		class ExplicitMixedPathTypesLocationsTestCase {
 		}
 
 		return Arrays.asList(new Object[][] {
 
+			{ ClasspathNonExistentDefaultLocationsTestCase.class, new String[] {} },
+
 			{
-				ClasspathDefaultLocationsTestCase.class,
-				new String[] { "classpath:/org/springframework/test/context/support/GenericXmlContextLoaderResourceLocationsTests$1ClasspathDefaultLocationsTestCase-context.xml" } },
+				ClasspathExistentDefaultLocationsTestCase.class,
+				new String[] { "classpath:/org/springframework/test/context/support/GenericXmlContextLoaderResourceLocationsTests$1ClasspathExistentDefaultLocationsTestCase-context.xml" } },
 
 			{
 				ImplicitClasspathLocationsTestCase.class,
@@ -118,7 +123,7 @@ public class GenericXmlContextLoaderResourceLocationsTests {
 
 		final ContextConfiguration contextConfig = this.testClass.getAnnotation(ContextConfiguration.class);
 		final ContextLoader contextLoader = new GenericXmlContextLoader();
-		final String[] configuredLocations = (String[]) AnnotationUtils.getValue(contextConfig, "locations");
+		final String[] configuredLocations = (String[]) AnnotationUtils.getValue(contextConfig);
 		final String[] processedLocations = contextLoader.processLocations(this.testClass, configuredLocations);
 
 		if (logger.isDebugEnabled()) {
@@ -129,8 +134,7 @@ public class GenericXmlContextLoaderResourceLocationsTests {
 		}
 
 		assertArrayEquals("Verifying locations for test [" + this.testClass + "].", this.expectedLocations,
-				processedLocations);
+			processedLocations);
 	}
 
-
 }