AR.instantiate with hash when keys are symbols bug

ar_instantiate_test.rb

# Activate the gem you are reporting the issue against.
gem 'activerecord', '4.1.1'
require 'active_record'
require 'minitest/autorun'
require 'logger'

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts do |t|
    t.string :title
  end
end

class Post < ActiveRecord::Base
end

class BugTest < Minitest::Test

  # this fails
  def test_instantiate_hash_with_keys_as_symbols
    post = Post.instantiate title: "Hello world!"

    assert_equal "Hello world!", post.title
  end

  # this passes
  def test_instantiate_hash_with_keys_as_strings
    post = Post.instantiate "title" => "Hello world 2!"

    assert_equal "Hello world 2!", post.title
  end
end