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Testing Database Schema Operations in Paperclip

This RSpec test suite validates the database schema functionality of Paperclip attachments, focusing on column creation, management, and migration capabilities. It ensures proper handling of file attachments in database tables through comprehensive testing of schema modifications and attachment-related operations.

Test Coverage Overview

The test suite provides extensive coverage of Paperclip’s schema operations, including:

Table definition scenarios for single and multiple attachments
Migration workflows for adding and removing attachment columns
Default value handling for attachment attributes
Edge cases for invalid attachment operations
Deprecation warnings for legacy methods

Implementation Analysis

The testing approach utilizes RSpec’s behavior-driven development patterns with nested contexts for different scenarios. It employs ActiveSupport’s testing utilities for deprecation handling and leverages database manipulation through connection adapters. The implementation validates both modern and legacy attachment methods.

Technical Details

Key technical components include:

RSpec for test structure and assertions
ActiveSupport::Testing::Deprecation for deprecation handling
Database connection manipulation for schema changes
Custom matchers for column validation
Table recreation between tests for isolation

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Proper test isolation through table rebuilding
Comprehensive context organization
Explicit expectation setting
Clear separation of concerns between different schema operations
Thorough error case handling

thoughtbot/paperclip

spec/paperclip/schema_spec.rb

            
require 'spec_helper'
require 'paperclip/schema'
require 'active_support/testing/deprecation'

describe Paperclip::Schema do
  include ActiveSupport::Testing::Deprecation

  before do
    rebuild_class
  end

  after do
    Dummy.connection.drop_table :dummies rescue nil
  end

  context "within table definition" do
    context "using #has_attached_file" do
      before do
        ActiveSupport::Deprecation.silenced = false
      end
      it "creates attachment columns" do
        Dummy.connection.create_table :dummies, force: true do |t|
          ActiveSupport::Deprecation.silence do
            t.has_attached_file :avatar
          end
        end

        columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

        expect(columns).to include(['avatar_file_name', "varchar"])
        expect(columns).to include(['avatar_content_type', "varchar"])
        expect(columns).to include(['avatar_file_size', "bigint"])
        expect(columns).to include(['avatar_updated_at', "datetime"])
      end

      it "displays deprecation warning" do
        Dummy.connection.create_table :dummies, force: true do |t|
          assert_deprecated do
            t.has_attached_file :avatar
          end
        end
      end
    end

    context "using #attachment" do
      before do
        Dummy.connection.create_table :dummies, force: true do |t|
          t.attachment :avatar
        end
      end

      it "creates attachment columns" do
        columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

        expect(columns).to include(['avatar_file_name', "varchar"])
        expect(columns).to include(['avatar_content_type', "varchar"])
        expect(columns).to include(['avatar_file_size', "bigint"])
        expect(columns).to include(['avatar_updated_at', "datetime"])
      end
    end

    context "using #attachment with options" do
      before do
        Dummy.connection.create_table :dummies, force: true do |t|
          t.attachment :avatar, default: 1, file_name: { default: 'default' }
        end
      end

      it "sets defaults on columns" do
        defaults_columns = ["avatar_file_name", "avatar_content_type", "avatar_file_size"]
        columns = Dummy.columns.select { |e| defaults_columns.include? e.name }

        expect(columns).to have_column("avatar_file_name").with_default("default")
        expect(columns).to have_column("avatar_content_type").with_default("1")
        expect(columns).to have_column("avatar_file_size").with_default(1)
      end
    end
  end

  context "within schema statement" do
    before do
      Dummy.connection.create_table :dummies, force: true
    end

    context "migrating up" do
      context "with single attachment" do
        before do
          Dummy.connection.add_attachment :dummies, :avatar
        end

        it "creates attachment columns" do
          columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

          expect(columns).to include(['avatar_file_name', "varchar"])
          expect(columns).to include(['avatar_content_type', "varchar"])
          expect(columns).to include(['avatar_file_size', "bigint"])
          expect(columns).to include(['avatar_updated_at', "datetime"])
        end
      end

      context "with single attachment and options" do
        before do
          Dummy.connection.add_attachment :dummies, :avatar, default: '1', file_name: { default: 'default' }
        end

        it "sets defaults on columns" do
          defaults_columns = ["avatar_file_name", "avatar_content_type", "avatar_file_size"]
          columns = Dummy.columns.select { |e| defaults_columns.include? e.name }

          expect(columns).to have_column("avatar_file_name").with_default("default")
          expect(columns).to have_column("avatar_content_type").with_default("1")
          expect(columns).to have_column("avatar_file_size").with_default(1)
        end
      end

      context "with multiple attachments" do
        before do
          Dummy.connection.add_attachment :dummies, :avatar, :photo
        end

        it "creates attachment columns" do
          columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

          expect(columns).to include(['avatar_file_name', "varchar"])
          expect(columns).to include(['avatar_content_type', "varchar"])
          expect(columns).to include(['avatar_file_size', "bigint"])
          expect(columns).to include(['avatar_updated_at', "datetime"])
          expect(columns).to include(['photo_file_name', "varchar"])
          expect(columns).to include(['photo_content_type', "varchar"])
          expect(columns).to include(['photo_file_size', "bigint"])
          expect(columns).to include(['photo_updated_at', "datetime"])
        end
      end

      context "with multiple attachments and options" do
        before do
          Dummy.connection.add_attachment :dummies, :avatar, :photo, default: '1', file_name: { default: 'default' }
        end

        it "sets defaults on columns" do
          defaults_columns = ["avatar_file_name", "avatar_content_type", "avatar_file_size", "photo_file_name", "photo_content_type", "photo_file_size"]
          columns = Dummy.columns.select { |e| defaults_columns.include? e.name }

          expect(columns).to have_column("avatar_file_name").with_default("default")
          expect(columns).to have_column("avatar_content_type").with_default("1")
          expect(columns).to have_column("avatar_file_size").with_default(1)
          expect(columns).to have_column("photo_file_name").with_default("default")
          expect(columns).to have_column("photo_content_type").with_default("1")
          expect(columns).to have_column("photo_file_size").with_default(1)
        end
      end

      context "with no attachment" do
        it "raises an error" do
          assert_raises ArgumentError do
            Dummy.connection.add_attachment :dummies
          end
        end
      end
    end

    context "migrating down" do
      before do
        Dummy.connection.change_table :dummies do |t|
          t.column :avatar_file_name, :string
          t.column :avatar_content_type, :string
          t.column :avatar_file_size, :bigint
          t.column :avatar_updated_at, :datetime
        end
      end

      context "using #drop_attached_file" do
        before do
          ActiveSupport::Deprecation.silenced = false
        end
        it "removes the attachment columns" do
          ActiveSupport::Deprecation.silence do
            Dummy.connection.drop_attached_file :dummies, :avatar
          end

          columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

          expect(columns).to_not include(['avatar_file_name', "varchar"])
          expect(columns).to_not include(['avatar_content_type', "varchar"])
          expect(columns).to_not include(['avatar_file_size', "bigint"])
          expect(columns).to_not include(['avatar_updated_at', "datetime"])
        end

        it "displays a deprecation warning" do
          assert_deprecated do
            Dummy.connection.drop_attached_file :dummies, :avatar
          end
        end
      end

      context "using #remove_attachment" do
        context "with single attachment" do
          before do
            Dummy.connection.remove_attachment :dummies, :avatar
          end

          it "removes the attachment columns" do
            columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

            expect(columns).to_not include(['avatar_file_name', "varchar"])
            expect(columns).to_not include(['avatar_content_type', "varchar"])
            expect(columns).to_not include(['avatar_file_size', "bigint"])
            expect(columns).to_not include(['avatar_updated_at', "datetime"])
          end
        end

        context "with multiple attachments" do
          before do
            Dummy.connection.change_table :dummies do |t|
              t.column :photo_file_name, :string
              t.column :photo_content_type, :string
              t.column :photo_file_size, :bigint
              t.column :photo_updated_at, :datetime
            end

            Dummy.connection.remove_attachment :dummies, :avatar, :photo
          end

          it "removes the attachment columns" do
            columns = Dummy.columns.map{ |column| [column.name, column.sql_type] }

            expect(columns).to_not include(['avatar_file_name', "varchar"])
            expect(columns).to_not include(['avatar_content_type', "varchar"])
            expect(columns).to_not include(['avatar_file_size', "bigint"])
            expect(columns).to_not include(['avatar_updated_at', "datetime"])
            expect(columns).to_not include(['photo_file_name', "varchar"])
            expect(columns).to_not include(['photo_content_type', "varchar"])
            expect(columns).to_not include(['photo_file_size', "bigint"])
            expect(columns).to_not include(['photo_updated_at', "datetime"])
          end
        end

        context "with no attachment" do
          it "raises an error" do
            assert_raises ArgumentError do
              Dummy.connection.remove_attachment :dummies
            end
          end
        end
      end
    end
  end
end