How to properly do model testing with ActiveStorage in rails?

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  endend

After

describe '#image' do  subject { create(:culture).image }  it { is_expected.to be_an_instance_of(ActiveStorage::Attached::One) }end

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

Here is how I solved it

# modelclass Report < ApplicationRecord  has_one_attached :fileend

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

# specrequire '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  endend

I hope it help you