Testing shrine validations with RSpec

avatar_uploader.rb

# app/uploaders/avatar_uploader.rb

class AvatarUploader < Shrine
  plugin :validation_helpers

  Attacher.validate do
    validate_mime_type_inclusion %w[image/jpeg]
    validate_max_size 10.megabytes
  end
end

shrine.rb

# spec/support/shrine.rb

# frozen_string_literal: true

require 'shrine/storage/memory'

include ActionDispatch::TestProcess

RSpec.configure do |config|
  config.before(:suite) do
    image = fixture_file_upload(Rails.root.join('spec', 'support',
                                                'images',
                                                'real_image.jpg'))
    Shrine.storages[:store].upload(image, 'real_image.jpg')
  end
end

shrine_init.rb

# config/initializers/shrine.rb

require 'shrine'

if Rails.env.production? || Rails.env.staging?
  require 'shrine/storage/s3'
  require 'shrine/storage/file_system'

  s3_options = {
    access_key_id: ENV['AWS_ACCESS_KEY_ID'],
    secret_access_key: ENV['AWS_SECRET_ACCESS_KEY'],
    region: ENV['AWS_REGION'],
    bucket: ENV['S3_BUCKET_NAME']
  }

  Shrine.storages = {
    cache: Shrine::Storage::FileSystem.new('tmp', prefix: 'uploads/cache'),
    store: Shrine::Storage::S3.new(**s3_options)
  }

  Shrine.plugin :logging, logger: Rails.logger
else
  require 'shrine/storage/memory'

  Shrine.storages = {
    cache: Shrine::Storage::Memory.new,
    store: Shrine::Storage::Memory.new
  }
end

Shrine.plugin :activerecord
Shrine.plugin :determine_mime_type
Shrine.plugin :cached_attachment_data
Shrine.plugin :restore_cached_data
Shrine.plugin :delete_promoted
Shrine.plugin :delete_raw
Shrine.plugin :remove_invalid

user.rb

# spec/support/factories/user.rb

FactoryBot.define do
  factory :user do
    avatar do
      Shrine.uploaded_file(
        'id'       => 'real_image.jpg',
        'storage'  => 'store',
        'metadata' => { 'mime_type' => 'image/jpeg', 'size' => 100 }
      )
    end
  end
end

user_spec.rb

# spec/models/user_spec.rb

require 'rails_helper'

RSpec.describe User, type: :model do
  describe 'avatar' do
    context 'with improper mime type' do
      let(:faulty_avatar) do
        Shrine.uploaded_file(
          'id'       => 'real_image.jpg',
          'storage'  => 'store',
          'metadata' => { 'mime_type' => 'text/plain', 'size' => 11.megabytes }
        )
      end

      before do
        basic_details.update(avatar: faulty_avatar)
      end

      it 'is not of allowed type' do
        expect(basic_details.errors[:avatar])
          .to include("isn't of allowed type (allowed types: image/jpeg)")
      end

      it 'is not within upload limits' do
        expect(basic_details.errors[:avatar])
          .to include('is too large (max is 10.0 MB)')
      end
    end
  end
end