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class ActiveStorage::FixtureSet

Active Storage FixtureSet

Fixtures are a way of organizing data that you want to test against; in short, sample data.

To learn more about fixtures, read the ActiveRecord::FixtureSet documentation.


Like other Active Record-backed models, ActiveStorage::Attachment and ActiveStorage::Blob records inherit from ActiveRecord::Base instances and therefore can be populated by fixtures.

Consider a hypothetical Article model class, its related fixture data, as well as fixture data for related ActiveStorage::Attachment and ActiveStorage::Blob records:

# app/models/article.rb
class Article < ApplicationRecord
  has_one_attached :thumbnail

# fixtures/active_storage/blobs.yml
first_thumbnail_blob: <%= ActiveStorage::FixtureSet.blob filename: "first.png" %>

# fixtures/active_storage/attachments.yml
  name: thumbnail
  record: first (Article)
  blob: first_thumbnail_blob

When processed, Active Record will insert database records for each fixture entry and will ensure the Active Storage relationship is intact.

Inherits From

Public class methods

Generate a YAML-encoded representation of an ActiveStorage::Blob instance’s attributes, resolve the file relative to the directory mentioned by ActiveSupport::Testing::FileFixtures.file_fixture, and upload the file to the Service


# tests/fixtures/active_storage/blobs.yml
second_thumbnail_blob: <%= ActiveStorage::FixtureSet.blob(
  filename: "second.svg",
) %>

third_thumbnail_blob: <%= ActiveStorage::FixtureSet.blob(
  filename: "third.svg",
  content_type: "image/svg+xml",
  service_name: "public"
) %>
Source code GitHub
# File activestorage/lib/active_storage/fixture_set.rb, line 66
def self.blob(filename:, **attributes)
  new.prepare filename, key: generate_unique_secure_token), **attributes

Public instance methods

Source code GitHub
# File activestorage/lib/active_storage/fixture_set.rb, line 70
def prepare(instance, **attributes)
  io = file_fixture(instance.filename.to_s).open

  instance.attributes.transform_values { |value| value.is_a?(Hash) ? value.to_json : value }.compact.to_json

Definition files