Allow mongodb to accept uri instead of hash

lib/moneta/adapters/mongodb.rb

@@ -11,14 +11,19 @@ class MongoDB
       include Moneta::Defaults
 
       def initialize(options = {})
-        options = {
-          :host => ENV['MONGO_RUBY_DRIVER_HOST'] || 'localhost',
-          :port => ENV['MONGO_RUBY_DRIVER_PORT'] || Mongo::Connection::DEFAULT_PORT,
-          :db => 'cache',
-          :collection => 'cache'
-        }.update(options)
-        conn = Mongo::Connection.new(options[:host], options[:port])
-        @cache = conn.db(options[:db]).collection(options[:collection])
+        if options[:uri]
+          db = Mongo::Connection.from_uri options[:uri]
+        else
+          options = {
+            :host => ENV['MONGO_RUBY_DRIVER_HOST'] || 'localhost',
+            :port => ENV['MONGO_RUBY_DRIVER_PORT'] || Mongo::Connection::DEFAULT_PORT,
+            :db => 'cache',
+            :collection => 'cache'
+          }.update(options)
+          conn = Mongo::Connection.new(options[:host], options[:port])
+          db = conn.db(options[:db])
+        end
+        @cache = db.collection(options[:collection])
       end
 
       def key?(key, *)

spec/moneta_mongodb_spec.rb

@@ -9,12 +9,29 @@
       @cache.clear
     end
 
-    it_should_behave_like "a read/write Moneta cache"
+    describe '#initialize' do
+      it 'should initialize with a URI' do
+        mock_mongo = mock(Mongo::Connection, :collection => [])
+        Mongo::Connection.should_receive(:from_uri).
+          with('mongodb://a:b@localhost:27059/cache').
+          and_return mock_mongo
+        m = Moneta::Adapters::MongoDB.new :uri => 'mongodb://a:b@localhost:27059/cache'
+      end
+      it 'should initialize with a hash of options' do
+        m = Moneta::Adapters::MongoDB.new
+        m['example'] = 3.0
+        m['example'].should == 3.0
+      end
+    end
+
+    context 'initialized' do
+      it_should_behave_like "a read/write Moneta cache"
 
-    describe '#store' do
-      it 'should store marshalled data that contains "invalid" UTF-8 characters' do
-        expect { @cache['example'] = 17.8 }.
-          should_not raise_error
+      describe '#store' do
+        it 'should store marshalled data that contains "invalid" UTF-8 characters' do
+          expect { @cache['example'] = 17.8 }.
+            should_not raise_error
+        end
       end
     end
   end