Add ruler for unnecessary double quotes, refs turboladen#91.

features/valid_ruby.feature

@@ -7,7 +7,7 @@ Feature: Valid Ruby
     Given a file named "extra_end.rb" with:
     """
     def a_method
-      puts "stuff"
+      puts 'stuff'
     end
     end
 

lib/tailor/cli/options.rb

@@ -75,6 +75,12 @@ def self.parse!(args)
             options.style[:allow_trailing_line_spaces] = c
           end
 
+          opt.on('--allow-unnecessary-double-quotes BOOL',
+            'Check for unnecessary use of double quotes?',
+            '(default: false)') do |c|
+            options.style[:allow_unnecessary_double_quotes] = c
+          end
+
           opt.on('--indentation-spaces NUMBER', IntegerOrOff,
             'Spaces to expect indentation.  (default: 2)') do |c|
             options.style[:indentation_spaces] = c

lib/tailor/configuration/style.rb

@@ -29,6 +29,7 @@ def self.define_property(name)
       define_property :allow_hard_tabs
       define_property :allow_screaming_snake_case_classes
       define_property :allow_trailing_line_spaces
+      define_property :allow_unnecessary_double_quotes
       define_property :allow_invalid_ruby
       define_property :indentation_spaces
       define_property :max_code_lines_in_class
@@ -53,6 +54,7 @@ def initialize
         allow_hard_tabs(false, level: :error)
         allow_screaming_snake_case_classes(false, level: :error)
         allow_trailing_line_spaces(false, level: :error)
+        allow_unnecessary_double_quotes(false, level: :warn)
         allow_invalid_ruby(false, level: :warn)
         indentation_spaces(2, level: :error)
         max_code_lines_in_class(300, level: :error)

lib/tailor/rulers/allow_unnecessary_double_quotes_ruler.rb

@@ -0,0 +1,63 @@
+require_relative '../ruler'
+
+class Tailor
+  module Rulers
+    class AllowUnnecessaryDoubleQuotesRuler < Tailor::Ruler
+
+      def initialize(config, options)
+        super(config, options)
+        add_lexer_observers :nl
+      end
+
+      def nl_update(lexed_line, lineno, column)
+        quotes(lexed_line).each do |quote|
+          unless contains_embedded_expression?(quote) ||
+            contains_escape_sequence?(quote)
+            measure(lineno, column(quote.first))
+          end
+        end
+      end
+
+      # Checks to see if the double_quotes are unnecessary.
+      #
+      # @param [Fixnum] lineno Line the problem was found on.
+      # @param [Fixnum] column Column the problem was found on.
+      def measure(lineno, column)
+        @problems << Problem.new('unnecessary_double_quotes', lineno, column,
+          "Unnecessary double quotes at column #{column}, " +
+            'expected single quotes.', @options[:level])
+      end
+
+      private
+
+      def contains_embedded_expression?(tokens)
+        tokens.any? { |t| t[1] == :on_embexpr_beg }
+      end
+
+      def contains_escape_sequence?(tokens)
+        tokens.any? do |t|
+          t[1] == :on_tstring_content and t[2].match(/\\[a-z]+/)
+        end
+      end
+
+      def quotes(tokens)
+        tokens.select do |t|
+          true if (double_quote_start?(t))..(double_quote_end?(t))
+        end.slice_before { |t| double_quote_start?(t) }.reject { |q| q.empty? }
+      end
+
+      def column(token)
+        token[0][1]
+      end
+
+      def double_quote_start?(token)
+        token[1] == :on_tstring_beg and token[2] == '"'
+      end
+
+      def double_quote_end?(token)
+        token[1] == :on_tstring_end and token[2] == '"'
+      end
+
+    end
+  end
+end

spec/functional/horizontal_spacing/hard_tabs_spec.rb

@@ -9,13 +9,13 @@
 
 HARD_TABS['hard_tab'] =
   %Q{def something
-\tputs "something"
+\tputs 'something'
 end}
 
 HARD_TABS['hard_tab_with_spaces'] =
   %Q{class Thing
   def something
-\t  puts "something"
+\t  puts 'something'
   end
 end}
 
@@ -27,14 +27,14 @@ def something
 HARD_TABS['hard_tab_with_1_indented_space'] =
   %Q{class Thing
   def something
-\t   puts "something"
+\t   puts 'something'
   end
 end}
 
 HARD_TABS['hard_tab_with_2_indented_spaces'] =
   %Q{class Thing
   def something
-\t    puts "something"
+\t    puts 'something'
   end
 end}
 

spec/functional/string_quoting_spec.rb

@@ -0,0 +1,97 @@
+require 'spec_helper'
+require_relative '../support/string_quoting_cases'
+require 'tailor/critic'
+require 'tailor/configuration/style'
+
+describe 'String Quoting' do
+
+  def file_name
+    self.class.description
+  end
+
+  def contents
+    QUOTING[file_name] || begin
+      raise "Example not found: #{file_name}"
+    end
+  end
+
+  before do
+    Tailor::Logger.stub(:log)
+    FakeFS.activate!
+    FileUtils.touch file_name
+    File.open(file_name, 'w') { |f| f.write contents }
+  end
+
+  let(:critic) { Tailor::Critic.new }
+
+  let(:style) do
+    style = Tailor::Configuration::Style.new
+    style.trailing_newlines 0, level: :off
+    style.allow_invalid_ruby true, level: :off
+    style
+  end
+
+  context :single_quotes_no_interpolation do
+    it 'does not warn' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to be_empty
+    end
+  end
+
+  context :double_quotes_with_interpolation do
+    it 'does not warn' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to be_empty
+    end
+  end
+
+  context :double_quotes_no_interpolation do
+    it 'warns that double quotes are unnecessary' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to eql [{
+        :type => 'unnecessary_double_quotes',
+        :line => 1,
+        :column => 6,
+        :message => 'Unnecessary double quotes at column 6, expected single quotes.',
+        :level => :warn
+      }]
+    end
+  end
+
+  context :double_quotes_no_interpolation_twice do
+    it 'warns that double quotes are unnecessary' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to eql [
+        {
+          :type => 'unnecessary_double_quotes',
+          :line => 1,
+          :column => 6,
+          :message => 'Unnecessary double quotes at column 6, expected single quotes.',
+          :level => :warn
+        },
+        {
+          :type => 'unnecessary_double_quotes',
+          :line => 1,
+          :column => 14,
+          :message => 'Unnecessary double quotes at column 14, expected single quotes.',
+          :level => :warn
+        }
+      ]
+    end
+  end
+
+  context :nested_quotes do
+    it 'does not warn' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to be_empty
+    end
+  end
+
+  context :escape_sequence do
+    it 'does not warn when a double quoted string contains a newline' do
+      critic.check_file(file_name, style.to_hash)
+      expect(critic.problems[file_name]).to be_empty
+    end
+  end
+
+end

spec/functional/vertical_spacing/class_length_spec.rb

@@ -10,7 +10,7 @@
   include Pizza
 
   def barrel_roll
-    puts "DOABARRELROLL!"
+    puts 'DOABARRELROLL!'
   end
 end}
 

spec/support/bad_indentation_cases.rb

@@ -28,20 +28,20 @@
 
 INDENT_1['def_content_indented_end'] =
   %Q{def a
-  puts "stuff"
+  puts 'stuff'
  end}
 
 INDENT_1['class_def_content_outdented_end'] =
   %Q{class A
   def a
-    puts "stuff"
+    puts 'stuff'
  end
 end}
 
 INDENT_1['class_def_outdented_content'] =
   %Q{class A
   def a
-   puts "stuff"
+   puts 'stuff'
   end
 end}
 
@@ -56,85 +56,85 @@ def self.my_method
   %Q{def my_method
    case true
   when true
-    puts "stuff"
+    puts 'stuff'
   when false
-    puts "blah blah"
+    puts 'blah blah'
   end
 end}
 
 INDENT_1['case_indented_whens_level_trailing_comment'] =
   %Q{def my_method
    case true        # comment
   when true
-    puts "stuff"
+    puts 'stuff'
   when false
-    puts "blah blah"
+    puts 'blah blah'
   end
 end}
 
 INDENT_1['case_outdented_whens_level'] =
   %Q{def my_method
  case true
   when true
-    puts "stuff"
+    puts 'stuff'
   when false
-    puts "blah blah"
+    puts 'blah blah'
   end
 end}
 
 INDENT_1['case_when_indented_whens_level'] =
   %Q{def my_method
   case true
    when true
-    puts "stuff"
+    puts 'stuff'
   when false
-    puts "blah blah"
+    puts 'blah blah'
   end
 end}
 
 INDENT_1['case_when_outdented_whens_level'] =
   %Q{def my_method
   case true
  when true
-    puts "stuff"
+    puts 'stuff'
   when false
-    puts "blah blah"
+    puts 'blah blah'
   end
 end}
 
 INDENT_1['case_indented_whens_in'] =
   %Q{def my_method
    case true
     when true
-      puts "stuff"
+      puts 'stuff'
     when false
-      puts "blah blah"
+      puts 'blah blah'
   end
 end}
 
 INDENT_1['while_do_indented'] =
   %Q{ while true do
-  puts "something"
+  puts 'something'
 end}
 
 INDENT_1['while_do_outdented'] =
   %Q{def my_method
  while true do
-    puts "something"
+    puts 'something'
   end
 end}
 
 INDENT_1['while_do_content_outdented'] =
   %Q{def my_method
   while true do
-   puts "something"
+   puts 'something'
   end
 end}
 
 INDENT_1['while_do_content_indented'] =
   %Q{def my_method
   while true do
-     puts "something"
+     puts 'something'
   end
 end}
 
@@ -240,7 +240,7 @@ def self.my_method
  '/profiles/DVR5000/ssdp_notification.erb'}
 
 INDENT_1['multi_line_method_call_end_in'] =
-  %Q{def initialize(raw_response)
+  %q{def initialize(raw_response)
   if raw_response.nil? || raw_response.empty?
     raise RTSP::Error,
       "#{self.class} received nil string--this shouldn't happen."