[117424] update test case to avoid passing null args into API that assumes non-null args.  Added Assert to code to make assumption more explicit.
diff --git a/bundles/org.eclipse.wst.xml.core/src/org/eclipse/wst/xml/core/internal/modelquery/XMLCatalogIdResolver.java b/bundles/org.eclipse.wst.xml.core/src/org/eclipse/wst/xml/core/internal/modelquery/XMLCatalogIdResolver.java
index 9b74bde..0a24f26 100644
--- a/bundles/org.eclipse.wst.xml.core/src/org/eclipse/wst/xml/core/internal/modelquery/XMLCatalogIdResolver.java
+++ b/bundles/org.eclipse.wst.xml.core/src/org/eclipse/wst/xml/core/internal/modelquery/XMLCatalogIdResolver.java
@@ -15,6 +15,7 @@
 
 import org.eclipse.wst.common.uriresolver.internal.provisional.URIResolverPlugin;
 import org.eclipse.wst.common.uriresolver.internal.util.URIHelper;
+import org.eclipse.wst.sse.core.internal.util.Assert;
 import org.eclipse.wst.sse.core.internal.util.URIResolver;
 import org.eclipse.wst.xml.core.internal.Logger;
 
@@ -59,14 +60,14 @@
 	public String resolve(String base, String publicId, String systemId) {
 
 		String result = systemId;
-		
 		if (base == null) {
-			base = getResourceLocation();
-			// bug 117320, ensure base URI is 'protocal' qualified before passing it thru to URIResolver
-			base= URIHelper.addImpliedFileProtocol(base);
+		  base = getResourceLocation();
+		  // bug 117320, ensure base URI is 'protocal' qualified before passing it thru to URIResolver
+		  // bug 117424, we should be able to assume that the base location is non-null
+	      Assert.isNotNull(base, "Base location is expected to be non null.");
+		  base = URIHelper.addImpliedFileProtocol(base);			 
 		}
-		
-		result = URIResolverPlugin.createResolver().resolve(base, publicId, systemId);	
+		result = URIResolverPlugin.createResolver().resolve(base, publicId, systemId);			  			
 		return result;
 	}