If method_missing gets called on criteria without another criteria, e…

…xpect array behaviour

lib/mongoid/criteria.rb

@@ -292,9 +292,13 @@ def merge(other)
     #
     # Returns: <tt>Criteria</tt>
     def method_missing(name, *args)
-      new_scope = @klass.send(name)
-      new_scope.merge(self)
-      new_scope
+      if @klass.respond_to?(name)
+        new_scope = @klass.send(name)
+        new_scope.merge(self)
+        return new_scope
+      else
+        return collect.send(name, *args)
+      end
     end
 
     # Adds a criterion to the +Criteria+ that specifies values where none
@@ -367,11 +371,6 @@ def per_page
       (@options[:limit] || 20).to_i
     end
 
-    # Execute the criteria and collect in order to handle random requests.
-    def rand
-      collect.rand
-    end
-
     # Adds a criterion to the +Criteria+ that specifies the fields that will
     # get returned from the Document. Used mainly for list views that do not
     # require all fields to be present. This is similar to SQL "SELECT" values.

spec/unit/mongoid/criteria_spec.rb

@@ -457,6 +457,34 @@
 
     end
 
+    context "when expecting behaviour of an array" do
+
+      before do
+        @array = mock
+        @document = mock
+      end
+
+      describe "#[]" do
+
+        it "collects the criteria and calls []" do
+          @criteria.expects(:collect).returns([@document])
+          @criteria[0].should == @document
+        end
+
+      end
+
+      describe "#rand" do
+
+        it "collects the criteria and call rand" do
+          @criteria.expects(:collect).returns(@array)
+          @array.expects(:send).with(:rand).returns(@document)
+          @criteria.rand
+        end
+
+      end
+
+    end
+
   end
 
   describe "#not_in" do