Do no warn when a double quote string contains a single quote.

lib/tailor/rulers/allow_unnecessary_double_quotes_ruler.rb

@@ -11,7 +11,8 @@ def initialize(config, options)
       def nl_update(lexed_line, lineno, _)
         quotes(lexed_line).each do |quote|
           unless contains_embedded_expression?(quote) ||
-            contains_escape_sequence?(quote)
+            contains_escape_sequence?(quote) ||
+            contains_single_quote?(quote)
             measure(lineno, column(quote.first))
           end
         end
@@ -39,6 +40,12 @@ def contains_escape_sequence?(tokens)
         end
       end
 
+      def contains_single_quote?(tokens)
+        tokens.any? do |t|
+          t[1] == :on_tstring_content and t[2].match(/'/)
+        end
+      end
+
       def quotes(tokens)
         tokens.select do |t|
           true if (double_quote_start?(t))..(double_quote_end?(t))

spec/functional/string_quoting_spec.rb

@@ -87,6 +87,13 @@ def contents
     end
   end
 
+  context :double_quotes_contains_single_quote 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)

spec/support/string_quoting_cases.rb

@@ -23,3 +23,7 @@
 QUOTING['nested_quotes'] =
   %q{foo = "foo#{bar('baz')}"
 }
+
+QUOTING['double_quotes_contains_single_quote'] =
+  %q{foo = "foo'd"
+}