Add a missing spec for String interpolation with class variables

Author: andrykonchin

spec/ruby/language/fixtures/class_with_class_variable.rb

@@ -0,0 +1,9 @@
+module StringSpecs
+  class ClassWithClassVariable
+    @@a = "xxx"
+
+    def foo
+      "#@@a"
+    end
+  end
+end

spec/ruby/language/string_spec.rb

@@ -1,6 +1,7 @@
 # -*- encoding: binary -*-
 
 require_relative '../spec_helper'
+require_relative 'fixtures/class_with_class_variable'
 
 # TODO: rewrite these horrid specs. it "are..." seriously?!
 
@@ -27,6 +28,11 @@
     "#$ip".should == 'xxx'
   end
 
+  it "interpolate class variables just with the # character" do
+    object = StringSpecs::ClassWithClassVariable.new
+    object.foo.should == 'xxx'
+  end
+
   it "allows underscore as part of a variable name in a simple interpolation" do
     @my_ip = 'xxx'
     "#@my_ip".should == 'xxx'
@@ -280,15 +286,15 @@ def long_string_literals
 
   it "creates a non-frozen String" do
     code = <<~'RUBY'
-    "a#{6*7}c"
+      "a#{6*7}c"
     RUBY
     eval(code).should_not.frozen?
   end
 
   it "creates a non-frozen String when # frozen-string-literal: true is used" do
     code = <<~'RUBY'
-    # frozen-string-literal: true
-    "a#{6*7}c"
+      # frozen-string-literal: true
+      "a#{6*7}c"
     RUBY
     eval(code).should_not.frozen?
   end