How to properly do model testing with ActiveStorage in rails?

Question

I have just switched to using ActiveStorage on rails 5.1.4 and I am new to TDD and struggling to figure out how to test a model that has_one_attached :avatar

Answer 1

I solved using

FactoryBot.define do
  factory :culture do
    name 'Soy'
    after(:build) do |culture|
      culture.image.attach(io: File.open(Rails.root.join('spec', 'factories', 'images', 'soy.jpeg')), filename: 'soy.jpeg', content_type: 'image/jpeg')
    end
  end
end

After

describe '#image' do
  subject { create(:culture).image }

  it { is_expected.to be_an_instance_of(ActiveStorage::Attached::One) }
end

Answer 2

Problem solved. After tracing the error to the ActiveStorage::Blob::upload method, where it said: Uploads the io to the service on the key for this blob. I realized I had not set the active_storage.service for the Test environment. Simply put, just add:

config.active_storage.service = :test

To config/environments/test.rb file

Answer 3

Here is how I solved it

# model
class Report < ApplicationRecord
  has_one_attached :file
end

# factory
FactoryBot.define do
  factory :report, class: Report do 
    any_extra_field { 'its value' }
  end
end

# spec
require 'rails_helper'
RSpec.describe Report, type: :model do
  context "with a valid file" do
    before(:each) do
      @report = create(:report)
    end

    it "is attached" do
      @report.file.attach(
        io: File.open(Rails.root.join('spec', 'fixtures', 'file_name.xlsx')),
        filename: 'filename.xlsx',
        content_type: 'application/xlsx'
      )
      expect(@report.file).to be_attached
    end
  end
end

I hope it help you

Answer 4

In config/environments/test.rb

config.active_storage.service = :test

In your spec

it {expect(valid_user.avatar).to be_attached}

Answer 5

I was running into a similar nil error (Module::DelegationError: to_model delegated to attachment, but attachment is nil), but it was only occurring when multiple tests were using the same factory.

The problem appears to be that the cleanup from the previous test's teardown was deleting the file after it was attached on the next factory call. The key was updating the ActiveJob queue adapter to inline so that the file would be deleted right away.

Add both of these settings to config/environments/test.rb:

# Use inline job processing to make things happen immediately
onfig.active_job.queue_adapter = :inline

# Store uploaded files on the local file system in a temporary directory.
config.active_storage.service = :test