# Users
User.create!(name:  "Example User",
             email: "example@railstutorial.org",
             password:              "foobar",
             password_confirmation: "foobar",
             admin: true,
             activated:    true,
             activated_at: Time.zone.now)
99.times do |n|
  name  = Faker::Name.name
  email = "example-#{n+1}@railstutorial.org"
  password = "password"
  User.create!(name:  name,
               email: email,
               password:              password,
               password_confirmation: password,
               activated:    true,
               activated_at: Time.zone.now)
end

# Microposts
users = User.order(:created_at).take(6)
image_path = File.join(Rails.root, "test/fixtures/images/sample.jpg")
50.times do
  content = Faker::Lorem.sentence(5)
  users.each { |user|
    # 画像と一緒にマイクロポストの初期データを作成する
    user.microposts.create!(content: content, picture: File.new(image_path))
  }
end

# Following relationships
users = User.all
user  = users.first
following = users[2..50]
followers = users[3..40]
following.each { |followed| user.follow(followed) }
followers.each { |follower| follower.follow(user) }

schema.rb
create_table "hoges"
 t.binary   "photo",       limit: 65535
end

path = Rails.root.join("画像が置いてあるパス")
photo = File.open(path, "rb").read

require 'active_record/fixtures'
  module FileFixtureExtension
    def file(file_name)
      File::open(Rails.root.join('test/fixtures/', file_name), 'rb') do |f|
        "!!binary "#{Base64.strict_encode64(f.read)}""
      end
    end
  end
ActiveRecord::Fixture.extend FileFixtureExtension

one:
  user: :one
  file: <%= ActiveRecord::Fixture::file 'files_to_upload/test.png' %>

sudo apt search ag|grep "silver"
    silversearcher-ag-el/xenial,xenial 0.46-2 all
sudo apt install silversearcher-ag

bundle exec rails test
.../config/initializers/file_fixtures_extension.rb:11:in `<top
(required)>': uninitialized constant Fixture (NameError)
from /home/d/.rvm/gems/ruby-2.4.0/gems/railties-5.1.4/lib/rails/engine.rb:655:in `block in load_config_initializer'

cd /home/d/.rvm/gems/ruby-2.4.0/gems
ag 'class Fixture '
activerecord-5.1.4/lib/active_record/fixtures.rb
11:  class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
412:  class FixtureSet
804:  class Fixture #:nodoc:
807:    class FixtureError < StandardError #:nodoc:

test "should update user" do
    #file = Rack::Test::UploadedFile.new(Rails.root.join("test/fixtures/files_to_upload/test.png"))
    file = fixture_file_upload('/files_to_upload/test.png','image/png')
    patch user_url(@user),
      params: {
        user: {
          name:'new name',
          file: file,
        }
    }
    assert_redirected_to user_url(@user)
  end