Fix simple RuboCop offenses and update TODO file (#1062)

* Fix Layout/EmptyLineAfterMagicComment offense

* Fix Layout/ExtraSpacing offense

* Fix Layout/ClosingParenthesisIndentation offenses

* Fix Style/MutableConstant offense

* Fix Style/UnneededInterpolation offenses

* Fix Style/RedundantParentheses offenses

* Update TODO config for RuboCop

* Add executable bit to test/test_helper.rb

ref: https://travis-ci.org/Shopify/liquid/jobs/488169512#L578

lib/liquid/expression.rb

@@ -19,7 +19,7 @@ module Liquid
       'false'.freeze => false,
       'blank'.freeze => MethodLiteral.new(:blank?, '').freeze,
       'empty'.freeze => MethodLiteral.new(:empty?, '').freeze
-    }
+    }.freeze
 
     SINGLE_QUOTED_STRING = /\A'(.*)'\z/m
     DOUBLE_QUOTED_STRING = /\A"(.*)"\z/m

lib/liquid/i18n.rb

@@ -26,7 +26,7 @@ module Liquid
     def interpolate(name, vars)
       name.gsub(/%\{(\w+)\}/) do
         # raise TranslationError, "Undefined key #{$1} for interpolation in translation #{name}"  unless vars[$1.to_sym]
-        "#{vars[$1.to_sym]}"
+        (vars[$1.to_sym]).to_s
       end
     end
 

lib/liquid/lexer.rb

@@ -12,7 +12,7 @@ module Liquid
       ')'.freeze => :close_round,
       '?'.freeze => :question,
       '-'.freeze => :dash
-    }
+    }.freeze
     IDENTIFIER = /[a-zA-Z_][\w-]*\??/
     SINGLE_STRING_LITERAL = /'[^\']*'/
     DOUBLE_STRING_LITERAL = /"[^\"]*"/

lib/liquid/standardfilters.rb

@@ -9,7 +9,7 @@ module Liquid
       '<'.freeze => '&lt;'.freeze,
       '"'.freeze => '&quot;'.freeze,
       "'".freeze => '&#39;'.freeze
-    }
+    }.freeze
     HTML_ESCAPE_ONCE_REGEXP = /["><']|&(?!([a-zA-Z]+|(#\d+));)/
 
     # Return the size of an array or of an string

lib/liquid/tags/if.rb

@@ -12,7 +12,7 @@ module Liquid
   class If < Block
     Syntax = /(#{QuotedFragment})\s*([=!<>a-z_]+)?\s*(#{QuotedFragment})?/o
     ExpressionsAndOperators = /(?:\b(?:\s?and\s?|\s?or\s?)\b|(?:\s*(?!\b(?:\s?and\s?|\s?or\s?)\b)(?:#{QuotedFragment}|\S+)\s*)+)/o
-    BOOLEAN_OPERATORS = %w(and or)
+    BOOLEAN_OPERATORS = %w(and or).freeze
 
     attr_reader :blocks
 

lib/liquid/variable_lookup.rb

@@ -1,7 +1,7 @@
 module Liquid
   class VariableLookup
     SQUARE_BRACKETED = /\A\[(.*)\]\z/m
-    COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze]
+    COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze].freeze
 
     attr_reader :name, :lookups
 

lib/liquid/version.rb

@@ -1,4 +1,5 @@
 # encoding: utf-8
+
 module Liquid
-  VERSION = "4.0.1"
+  VERSION = "4.0.1".freeze
 end