Failing test for has_many / dependent with foreign key

has_many_foreign_key.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 "activerecord", "5.0.0"
  gem "pg"
end

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

ActiveRecord::Base.establish_connection adapter: 'postgresql'
ActiveRecord::Base.connection.drop_database 'test_has_many_foreign_key'
ActiveRecord::Base.connection.create_database 'test_has_many_foreign_key'
ActiveRecord::Base.establish_connection adapter: 'postgresql', database: 'test_has_many_foreign_key'
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.references :post, foreign_key: true
    t.string :text
  end
end

class Post < ActiveRecord::Base
  has_many :comments, -> { where('text is not null') }, dependent: :destroy
end

class Comment < ActiveRecord::Base
end

class BugTest < Minitest::Test
  def test_has_many_foreign_key
    post = Post.create!
    empty = Comment.create! post_id: post.id
    valid = Comment.create! post_id: post.id, text: 'some text'

    post.destroy
    assert_equal 0, Post.count
  end
end