For testing on betawiki, prepend prefix to filename

As otherwise we will overwrite original files on commons

euroexange/euroexange.py

@@ -44,6 +44,11 @@ class EuroExangeBotJob():
         self.script = kwargs['script']
         self.freq = kwargs['freq']
 
+        # On beta prepend string TEST_ to filename to prevent overwriting of
+        # originial commons files
+        if pywikibot.Site().family.name == "wpbeta":
+            self.image = "TEST_{}".format(self.image)
+
 
 class EuroExangeBot( pywikibot.bot.BaseBot ):