Merge pull request #1041 from marcandre/mind_your_language

`Language::SelectorSet` tweaks

Author: pirj

lib/rubocop/rspec/language.rb

@@ -7,7 +7,8 @@ module Language
       # Set of method selectors
       class SelectorSet
         def initialize(selectors)
-          @selectors = selectors
+          @selectors = selectors.freeze
+          freeze
         end
 
         def ==(other)
@@ -50,6 +51,10 @@ def node_pattern
           selectors.map(&:inspect).join(' ')
         end
 
+        def to_a
+          selectors
+        end
+
         protected
 
         attr_reader :selectors