Bug 407888 - improve assert message

Change-Id: I9a42d1b56864ab9c53b0d695e146044346e94885
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
diff --git a/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/alias/BasicAliasTest.java b/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/alias/BasicAliasTest.java
index fa65f11..d7b01d4 100644
--- a/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/alias/BasicAliasTest.java
+++ b/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/alias/BasicAliasTest.java
@@ -716,7 +716,9 @@
 
 			//ensure aliases are gone (bug 144458)
 			final IResource[] aliases = aliasManager.computeAliases(folder, ((Folder) folder).getStore());
-			assertNull("4.0", aliases);
+			if (aliases != null) {
+				fail("Unexpected aliases: " + Arrays.toString(aliases));
+			}
 		} catch (CoreException e) {
 			fail("1.99", e);
 		}