handle case where string used for log device

This works in the base logger, but Methadone was asking
the string if it was a tty, which it isn't, but doesn't even respond to,
so beefing this up.

Closes #73

lib/methadone/cli_logger.rb

@@ -85,13 +85,16 @@ def initialize(log_device=$stdout,error_device=$stderr)
       super(log_device)
       @stderr_logger = Logger.new(error_device)
 
-      @split_logs = log_device.tty? && error_device.tty?
+      log_device_tty   = tty?(log_device)
+      error_device_tty = tty?(error_device)
+
+      @split_logs = log_device_tty && error_device_tty
 
       self.level = Logger::Severity::INFO
       @stderr_logger.level = DEFAULT_ERROR_LEVEL
 
-      self.formatter = BLANK_FORMAT if log_device.tty?
-      @stderr_logger.formatter = BLANK_FORMAT if error_device.tty?
+      self.formatter = BLANK_FORMAT if log_device_tty
+      @stderr_logger.formatter = BLANK_FORMAT if error_device_tty
     end
 
     def level=(level)
@@ -119,5 +122,12 @@ def error_formatter=(formatter)
       @stderr_logger.formatter=formatter
     end
 
+  private
+
+    def tty?(device_or_string)
+      return device_or_string.tty? if device_or_string.respond_to? :tty?
+      false
+    end
+
   end
 end

test/test_cli_logger.rb

@@ -1,6 +1,7 @@
 require 'base_test'
 require 'methadone'
 require 'stringio'
+require 'tempfile'
 
 class TestCLILogger < BaseTest
   include Methadone
@@ -158,6 +159,27 @@ def tty?; true; end
     }
   end
 
+  test_that "we can use filenames as log devices" do
+    Given {
+      tempfile = Tempfile.new("stderr_log")
+      @stdout_file = tempfile.path
+      tempfile.close
+
+      tempfile = Tempfile.new("stdout_log")
+      @stderr_file = tempfile.path
+      tempfile.close
+    }
+    When {
+      @logger = CLILogger.new(@stdout_file,@stderr_file)
+      @logger.info("some info")
+      @logger.error("some error")
+    }
+    Then {
+      File.read(@stdout_file).should =~ /some info/
+      File.read(@stderr_file).should =~ /some error/
+    }
+  end
+
   private 
 
   def log_all_levels