Enable debug mode when DEBUG environment variable is set

Author: p0deje

rb/lib/selenium/webdriver/common/logger.rb

@@ -115,13 +115,21 @@ def deprecate(old, new)
       def create_logger(output)
         logger = ::Logger.new(output)
         logger.progname = 'Selenium'
-        logger.level = ($DEBUG ? DEBUG : WARN)
+        logger.level = default_level
         logger.formatter = proc do |severity, time, progname, msg|
           "#{time.strftime('%F %T')} #{severity} #{progname} #{msg}\n"
         end
 
         logger
       end
+
+      def default_level
+        if $DEBUG || ENV.key?('DEBUG')
+          DEBUG
+        else
+          WARN
+        end
+      end
     end # Logger
   end # WebDriver
 end # Selenium