Add attempt to a test case for active storage

- I am having a hard time on where to locate the method and have access
to the method name and the instance so I can do something like:
```ruby
file_loader = FileLoader.new()
instance.send(method_name).attach(
  io: file_loader.io, filename: file_loader.filename
)
```

Gemfile

@@ -1,3 +1,6 @@
 source "https://rubygems.org"
 
 gemspec name: "factory_bot"
+
+gem 'pry'
+gem 'activestorage'

Gemfile.lock

@@ -7,12 +7,29 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
+    actionpack (5.2.3)
+      actionview (= 5.2.3)
+      activesupport (= 5.2.3)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.2)
+    actionview (5.2.3)
+      activesupport (= 5.2.3)
+      builder (~> 3.1)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
     activemodel (5.2.3)
       activesupport (= 5.2.3)
     activerecord (5.2.3)
       activemodel (= 5.2.3)
       activesupport (= 5.2.3)
       arel (>= 9.0)
+    activestorage (5.2.3)
+      actionpack (= 5.2.3)
+      activerecord (= 5.2.3)
+      marcel (~> 0.3.1)
     activesupport (5.2.3)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
@@ -35,8 +52,10 @@ GEM
     builder (3.2.3)
     childprocess (1.0.1)
       rake (< 13.0)
+    coderay (1.1.2)
     concurrent-ruby (1.1.5)
     contracts (0.16.0)
+    crass (1.0.4)
     cucumber (3.1.2)
       builder (>= 2.1.2)
       cucumber-core (~> 3.2.0)
@@ -55,18 +74,40 @@ GEM
     cucumber-wire (0.0.1)
     diff-lcs (1.3)
     docile (1.3.2)
+    erubi (1.8.0)
     ffi (1.11.1)
     gherkin (5.1.0)
     i18n (1.6.0)
       concurrent-ruby (~> 1.0)
     json (2.2.0)
+    loofah (2.2.3)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.5.9)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
+    method_source (0.9.2)
+    mimemagic (0.3.3)
+    mini_portile2 (2.4.0)
     minitest (5.11.3)
     multi_json (1.13.1)
     multi_test (0.1.2)
+    nokogiri (1.10.3)
+      mini_portile2 (~> 2.4.0)
     parallel (1.17.0)
     parser (2.6.3.0)
       ast (~> 2.4.0)
     powerpack (0.1.2)
+    pry (0.12.2)
+      coderay (~> 1.1.0)
+      method_source (~> 0.9.0)
+    rack (2.0.7)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
     rainbow (3.0.0)
     rake (12.3.2)
     rspec (3.8.0)
@@ -111,10 +152,12 @@ PLATFORMS
 
 DEPENDENCIES
   activerecord
+  activestorage
   appraisal
   aruba
   cucumber
   factory_bot!
+  pry
   rake
   rspec
   rspec-its

lib/factory_bot/definition_proxy.rb

@@ -160,20 +160,6 @@ def association(name, *options)
       end
     end
 
-    # Creates a copy of the file passed to attach to the attribute
-    #
-    # Arguments:
-    #   filepath: (String)
-    #     The path for the file that will be loaded. Should be a valid path
-    #     for a file that exists at that location.
-    #
-    # Returns:
-    #   An instance of the file loader class pointing to the file at the
-    #   provided path.
-    def file_fixture(file_path)
-      FileLoader.new(file_path)
-    end
-
     def to_create(&block)
       @definition.to_create(&block)
     end

lib/factory_bot/evaluator.rb

@@ -21,6 +21,20 @@ def initialize(build_strategy, overrides = {})
       end
     end
 
+    # Creates a copy of the file passed to attach to the attribute
+    #
+    # Arguments:
+    #   filepath: (String)
+    #     The path for the file that will be loaded. Should be a valid path
+    #     for a file that exists at that location.
+    #
+    # Returns:
+    #   An instance of the file loader class pointing to the file at the
+    #   provided path.
+    def file_fixture(file_path)
+      FileLoader.new(file_path)
+    end
+
     def association(factory_name, *traits_and_overrides)
       overrides = traits_and_overrides.extract_options!
       strategy_override = overrides.fetch(:strategy) do
@@ -37,10 +51,6 @@ def instance=(object_instance)
       @instance = object_instance
     end
 
-    def file_fixture(file_path)
-      FileLoader.new(file_path)
-    end
-
     def method_missing(method_name, *args, &block) # rubocop:disable Style/MethodMissing
       if @instance.respond_to?(method_name)
         @instance.send(method_name, *args, &block)

lib/factory_bot/file_loader.rb

@@ -8,10 +8,6 @@ def initialize(file_path)
       from_file_path(file_path)
     end
 
-    def path
-      tempfile.path
-    end
-
     def method_missing(method_name, *args, &block) # rubocop:disable Style/MethodMissing
       tempfile.public_send(method_name, *args, &block)
     end
@@ -20,6 +16,10 @@ def respond_to_missing?(method_name, include_private = false)
       tempfile.respond_to?(method_name, include_private) || super
     end
 
+    def io
+      tempfile.read
+    end
+
     private
 
     def from_file_path(path)

spec/acceptance/file_attributes_spec.rb

@@ -1,9 +1,25 @@
 describe "file attributes" do
+  class Attachment
+    attr_accessor :file
+
+    def initialize(file)
+      @file = file
+    end
+
+    def attach(*args); end
+  end
+
   context "when an attribute uses a file" do
     it "assigns an file to the attribute" do
       define_model("Post") do
+        def self.has_one_attached(*args); end
         has_one_attached :attachment
+        attr_accessor :attachment
+        def attachment=(value)
+          @attachment = Attachment.new(value)
+        end
       end
+
       filename = File.expand_path("spec/support/text_file.txt")
       file_contents = File.read(filename)
 
@@ -13,8 +29,11 @@
         end
       end
       post = FactoryBot.build(:post)
-      expect(post.attachment.original_filename).to eq ::File.basename filename
-      expect(File.read(post.attachment)).to eq file_contents
+      puts post.attachment.file.io
+      expect(post.attachment).to receive(:attach).with(
+        io: file_contents,
+        filename: filename,
+      )
     end
   end
 end

spec/support/macros/define_constant.rb

@@ -1,4 +1,5 @@
 require "active_record"
+require "active_storage"
 
 module DefineConstantMacros
   def define_class(path, base = Object, &block)
@@ -7,8 +8,12 @@ def define_class(path, base = Object, &block)
     const
   end
 
+  class ApplicationRecord < ActiveRecord::Base
+    include ActiveStorage
+  end
+
   def define_model(name, columns = {}, &block)
-    model = define_class(name, ActiveRecord::Base, &block)
+    model = define_class(name, ApplicationRecord, &block)
     create_table(model.table_name) do |table|
       columns.each do |column_name, type|
         table.column column_name, type