HashNuke#212 add dialog_present?/0 function

check for dialogs by reading from a dialog, if that fails assume the dialog is not present.

lib/hound/helpers/dialog.ex

@@ -3,6 +3,21 @@ defmodule Hound.Helpers.Dialog do
 
   import Hound.RequestUtils
 
+  @doc """
+  Checks if a dialog, javascript alert(), confirm() or prompt(), exists
+
+      dialog_present?()
+  """
+  @spec dialog_present?() :: Boolean.t
+  def dialog_present? do
+    try do
+      dialog_text()
+      true
+    rescue
+      RuntimeError -> false
+    end
+  end
+
   @doc """
   Gets text of a javascript alert(), confirm() or prompt().