[SPR-7326] MergedContextConfiguration now ensures that it holds non-null arrays with proper semantics for TestContext's cache key generation.

org.springframework.test/src/main/java/org/springframework/test/context/ContextLoaderUtils.java

@@ -18,9 +18,9 @@ package org.springframework.test.context;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
-import java.util.SortedSet;
-import java.util.TreeSet;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -243,10 +243,7 @@ abstract class ContextLoaderUtils {
 				annotationType, clazz));
 		}
 
-		// Active profiles must be sorted due to cache key generation in
-		// TestContext. Specifically, profile sets {foo,bar} and {bar,foo}
-		// must both result in the same array (e.g., [bar,foo]).
-		final SortedSet<String> activeProfiles = new TreeSet<String>();
+		final Set<String> activeProfiles = new HashSet<String>();
 
 		while (declaringClass != null) {
 			ActiveProfiles annotation = declaringClass.getAnnotation(annotationType);

org.springframework.test/src/main/java/org/springframework/test/context/MergedContextConfiguration.java

@@ -16,8 +16,13 @@
 
 package org.springframework.test.context;
 
+import java.util.Arrays;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
 import org.springframework.core.style.ToStringCreator;
 import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
 
 /**
  * TODO [SPR-8386] Document MergedContextConfiguration.
@@ -40,6 +45,26 @@ public class MergedContextConfiguration {
 	private final ContextLoader contextLoader;
 
 
+	private static String[] processLocations(String[] locations) {
+		return locations == null ? new String[] {} : locations;
+	}
+
+	private static Class<?>[] processClasses(Class<?>[] classes) {
+		return classes == null ? new Class<?>[] {} : classes;
+	}
+
+	private static String[] processActiveProfiles(String[] activeProfiles) {
+		if (activeProfiles == null) {
+			return new String[] {};
+		}
+
+		// Active profiles must be unique and sorted due to cache key generation
+		// in TestContext. Specifically, profile sets {foo,bar} and {bar,foo}
+		// must both result in the same array (e.g., [bar,foo]).
+		SortedSet<String> sortedProfilesSet = new TreeSet<String>(Arrays.asList(activeProfiles));
+		return StringUtils.toStringArray(sortedProfilesSet);
+	}
+
 	/**
 	 * TODO Document MergedContextConfiguration constructor.
 	 *
@@ -52,9 +77,9 @@ public class MergedContextConfiguration {
 	public MergedContextConfiguration(Class<?> testClass, String[] locations, Class<?>[] classes,
 			String[] activeProfiles, ContextLoader contextLoader) {
 		this.testClass = testClass;
-		this.locations = locations;
-		this.classes = classes;
-		this.activeProfiles = activeProfiles;
+		this.locations = processLocations(locations);
+		this.classes = processClasses(classes);
+		this.activeProfiles = processActiveProfiles(activeProfiles);
 		this.contextLoader = contextLoader;
 	}