XPath.match empty doc, nil doc test case added

Author: naitoh

test/xpath/test_base.rb

@@ -100,6 +100,16 @@ def test_root
       assert_equal "a", XPath::first( doc, "/" ).elements[1].name
     end
 
+    def test_empty_doc
+      assert_equal [], XPath.match([], '*')
+    end
+
+    def test_nil_doc
+      assert_raise(NoMethodError) {
+        XPath.match(nil, '*')
+      }
+    end
+
     def test_abbreviated_simple_child
       assert_equal "a", XPath::first(@@doc, "a").name
     end