Improve Buffer's unique key identifier

lib/redistat/buffer.rb

@@ -95,12 +95,15 @@ module Redistat
       end
     end
 
+    # depth_limit is not needed as it's evident in key.to_s
     def buffer_key(key, opts)
-      # depth_limit is not needed as it's evident in key.to_s
-      opts_index = Summary.default_options.keys.sort { |a,b| a.to_s <=> b.to_s }.map do |k|
-        opts[k] if opts.has_key?(k)
+      # covert keys to strings, as sorting a Hash with Symbol keys fails on
+      # Ruby 1.8.x.
+      opts = opts.inject({}) do |result, (k, v)|
+        result[k.to_s] = v
+        result
       end
-      "#{key.to_s}:#{opts_index.join(':')}"
+      "#{key.to_s}:#{opts.sort.flatten.join(':')}"
     end
 
   end

spec/buffer_spec.rb

@@ -78,9 +78,11 @@ describe Redistat::Buffer do
 
   it "should build #buffer_key correctly" do
     opts = {:enable_grouping => true, :label_indexing => false, :connection_ref => nil}
-    @buffer.send(:buffer_key, @key, opts).should == "#{@key.to_s}::true:false"
+    @buffer.send(:buffer_key, @key, opts).should ==
+      "#{@key.to_s}:connection_ref::enable_grouping:true:label_indexing:false"
     opts = {:enable_grouping => false, :label_indexing => true, :connection_ref => :omg}
-    @buffer.send(:buffer_key, @key, opts).should == "#{@key.to_s}:omg:false:true"
+    @buffer.send(:buffer_key, @key, opts).should ==
+      "#{@key.to_s}:connection_ref:omg:enable_grouping:false:label_indexing:true"
   end
 
   describe "Buffering" do