added test

Author: rpallavisharma

rb/spec/integration/selenium/webdriver/manager_spec.rb

@@ -257,6 +257,11 @@ module WebDriver
           expect { driver.manage.delete_cookie('') }
             .to raise_error(ArgumentError, /Cookie name cannot be null or empty/)
         end
+
+        it 'throws an error when cookie name is an empty string' do
+          expect { driver.manage.delete_cookie(nil) }
+            .to raise_error(ArgumentError, /Cookie name cannot be null or empty/)
+        end
       end
     end # Options
   end # WebDriver