firefox: Fixing "null pointer exception" in xpath location strategy. Fixes issue #714

Author: barancev

java/client/test/org/openqa/selenium/ElementFindingTest.java

@@ -404,6 +404,15 @@ public void testShouldBeAbleToFindElementByXPathWithNamespace() {
     assertThat(element.getText(), is("Test Chart"));
   }
 
+  @Ignore({IE, MARIONETTE, SAFARI, CHROME})
+  @NotYetImplemented(HTMLUNIT)
+  @Test
+  public void testShouldBeAbleToFindElementByXPathInXmlDocument() {
+    driver.get(pages.simpleXmlDocument);
+    WebElement element = driver.findElement(By.xpath("//foo"));
+    assertThat(element.getText(), is("baz"));
+  }
+
   // By.xpath negative
 
   @Test(expected = NoSuchElementException.class)

javascript/atoms/locators/xpath.js

@@ -119,7 +119,7 @@ bot.locators.xpath.evaluate_ = function(node, path, resultType) {
         for (var i = 0; i < allNodes.length; ++i) {
           var n = allNodes[i];
           var ns = n.namespaceURI;
-          if (!reversedNamespaces[ns]) {
+          if (ns && !reversedNamespaces[ns]) {
             var prefix = n.lookupPrefix(ns);
             if (!prefix) {
               var m = ns.match('.*/(\\w+)/?$');