Fix new rubocop warnings

test/controllers/api/amf_controller_test.rb

@@ -1390,8 +1390,8 @@ module Api
     def amf_content(target, ref, data)
       a, b = 1.divmod(256)
       c = StringIO.new
-      c.write 0.chr + 0.chr   # version 0
-      c.write 0.chr + 0.chr   # n headers
+      c.write 0.chr * 2       # version 0
+      c.write 0.chr * 2       # n headers
       c.write a.chr + b.chr   # n bodies
       c.write AMF.encodestring(target)
       c.write AMF.encodestring(ref)

test/lib/i18n_test.rb

@@ -63,13 +63,14 @@ class I18nTest < ActiveSupport::TestCase
     I18n.t(scope || ".", :locale => I18n.default_locale).map do |key, value|
       scoped_key = scope ? "#{scope}.#{key}" : key
 
-      if value.is_a?(Hash)
+      case value
+      when Hash
         if value.keys - plural_keys == []
           scoped_key
         else
           translation_keys(scoped_key)
         end
-      elsif value.is_a?(String)
+      when String
         scoped_key
       end
     end.flatten