Rails 4.2 ActiveRecord coerces String values to nil for jsonb fields #27236

issue_27236.rb

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  gem "rails", "4.2.7"
  gem "pg"
end

require "active_record"
require "minitest/autorun"
require "logger"

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

ActiveRecord::Schema.define do
  create_table :foos, force: true do |t|
    t.jsonb :bar
  end
end

class Foo < ActiveRecord::Base
end

class BugTest < Minitest::Test
  def test_association_stuff
    foo = Foo.new
    foo.bar = "test string"
    assert_equal "test string", foo.bar
  end
end