Add have_attached matcher for ActiveStorage (#1102)

lib/shoulda/matchers/active_record.rb

@@ -23,6 +23,7 @@ require "shoulda/matchers/active_record/accept_nested_attributes_for_matcher"
 require "shoulda/matchers/active_record/define_enum_for_matcher"
 require "shoulda/matchers/active_record/uniqueness"
 require "shoulda/matchers/active_record/validate_uniqueness_of_matcher"
+require "shoulda/matchers/active_record/have_attached_matcher"
 
 module Shoulda
   module Matchers

lib/shoulda/matchers/active_record/have_attached_matcher.rb

@@ -0,0 +1,147 @@
+module Shoulda
+  module Matchers
+    module ActiveRecord
+      def have_one_attached(name)
+        HaveAttachedMatcher.new(:one, name)
+      end
+
+      def have_many_attached(name)
+        HaveAttachedMatcher.new(:many, name)
+      end
+
+      # @private
+      class HaveAttachedMatcher
+        attr_reader :name
+
+        def initialize(macro, name)
+          @macro = macro
+          @name = name
+        end
+
+        def description
+          "have a has_#{macro}_attached called #{name}"
+        end
+
+        def failure_message
+          <<-MESSAGE
+Expected #{expectation}, but this could not be proved.
+  #{@failure}
+          MESSAGE
+        end
+
+        def failure_message_when_negated
+          <<-MESSAGE
+Did not expect #{expectation}, but it does.
+          MESSAGE
+        end
+
+        def expectation
+          "#{model_class.name} to #{description}"
+        end
+
+        def matches?(subject)
+          @subject = subject
+          reader_attribute_exists? &&
+            writer_attribute_exists? &&
+            attachments_association_exists? &&
+            blobs_association_exists? &&
+            eager_loading_scope_exists?
+        end
+
+        private
+
+        attr_reader :subject, :macro
+
+        def reader_attribute_exists?
+          if subject.respond_to?(name)
+            true
+          else
+            @failure = "#{model_class.name} does not have a :#{name} method."
+            false
+          end
+        end
+
+        def writer_attribute_exists?
+          if subject.respond_to?("#{name}=")
+            true
+          else
+            @failure = "#{model_class.name} does not have a :#{name}= method."
+            false
+          end
+        end
+
+        def attachments_association_exists?
+          if attachments_association_matcher.matches?(subject)
+            true
+          else
+            @failure = attachments_association_matcher.failure_message
+            false
+          end
+        end
+
+        def attachments_association_matcher
+          @_attachments_association_matcher ||=
+            AssociationMatcher.new(
+              :"has_#{macro}",
+              attachments_association_name,
+            ).
+              conditions(name: name).
+              class_name('ActiveStorage::Attachment').
+              inverse_of(:record)
+        end
+
+        def attachments_association_name
+          case macro
+          when :one then
+            "#{name}_attachment"
+          when :many then
+            "#{name}_attachments"
+          end
+        end
+
+        def blobs_association_exists?
+          if blobs_association_matcher.matches?(subject)
+            true
+          else
+            @failure = blobs_association_matcher.failure_message
+            false
+          end
+        end
+
+        def blobs_association_matcher
+          @_blobs_association_matcher ||=
+            AssociationMatcher.new(
+              :"has_#{macro}",
+              blobs_association_name,
+            ).
+              through(attachments_association_name).
+              class_name('ActiveStorage::Blob').
+              source(:blob)
+        end
+
+        def blobs_association_name
+          case macro
+          when :one then
+            "#{name}_blob"
+          when :many then
+            "#{name}_blobs"
+          end
+        end
+
+        def eager_loading_scope_exists?
+          if model_class.respond_to?("with_attached_#{name}")
+            true
+          else
+            @failure = "#{model_class.name} does not have a " \
+                       ":with_attached_#{name} scope."
+            false
+          end
+        end
+
+        def model_class
+          subject.class
+        end
+      end
+    end
+  end
+end

spec/support/unit/helpers/active_record_versions.rb

@@ -47,6 +47,10 @@ module UnitTests
       active_record_version >= 5
     end
 
+    def active_record_supports_active_storage?
+      active_record_version >= 5.2
+    end
+
     def active_record_supports_validate_presence_on_active_storage?
       active_record_version >= '6.0.0.beta1'
     end

spec/support/unit/helpers/rails_versions.rb

@@ -18,5 +18,9 @@ module UnitTests
     def rails_5_x?
       rails_version =~ '~> 5.0'
     end
+
+    def rails_gte_5_2?
+      rails_version >= 5.2
+    end
   end
 end

spec/unit/shoulda/matchers/active_record/have_attached_matcher_spec.rb

@@ -0,0 +1,272 @@
+require 'unit_spec_helper'
+
+describe Shoulda::Matchers::ActiveRecord::HaveAttachedMatcher, type: :model do
+  if active_record_supports_active_storage?
+    before do
+      create_table :active_storage_blobs do |t|
+        t.string :key, null: false
+        t.string :filename, null: false
+        t.string :content_type
+        t.text :metadata
+        t.bigint :byte_size, null: false
+        t.string :checksum, null: false
+        t.datetime :created_at, null: false
+
+        t.index [:key], unique: true
+      end
+
+      create_table :active_storage_attachments do |t|
+        t.string :name, null: false
+        t.references :record, null: false, polymorphic: true, index: false
+        t.references :blob, null: false
+
+        t.datetime :created_at, null: false
+
+        t.index [:record_type, :record_id, :name, :blob_id],
+          name: 'index_active_storage_attachments_uniqueness', unique: true
+
+        # The original rails migration has a foreign key.
+        # Since this messes up the clearing of the database, it's removed here.
+        # t.foreign_key :active_storage_blobs, column: :blob_id
+      end
+    end
+
+    describe 'have_one_attached' do
+      describe '#description' do
+        it 'returns the message with the name of the association' do
+          matcher = have_one_attached(:avatar)
+          expect(matcher.description).
+            to eq('have a has_one_attached called avatar')
+        end
+      end
+
+      context 'when the attached exists on the model' do
+        it 'matches' do
+          record = record_having_one_attached(:avatar)
+          expect { have_one_attached(:avatar) }.
+            to match_against(record).
+            or_fail_with(<<-MESSAGE)
+Did not expect User to have a has_one_attached called avatar, but it does.
+          MESSAGE
+        end
+
+        context 'and the reader attribute does not exist' do
+          it 'matches' do
+            record = record_having_one_attached(:avatar, remove_reader: true)
+            expect { have_one_attached(:avatar) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_one_attached called avatar, but this could not be proved.
+  User does not have a :avatar method.
+            MESSAGE
+          end
+        end
+
+        context 'and the writer attribute does not exist' do
+          it 'matches' do
+            record = record_having_one_attached(:avatar, remove_writer: true)
+            expect { have_one_attached(:avatar) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_one_attached called avatar, but this could not be proved.
+  User does not have a :avatar= method.
+            MESSAGE
+          end
+        end
+
+        context 'and the attachments association does not exist' do
+          it 'matches' do
+            record = record_having_one_attached(:avatar, remove_attachments: true)
+            expect { have_one_attached(:avatar) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_one_attached called avatar, but this could not be proved.
+  Expected User to have a has_one association called avatar_attachment (no association called avatar_attachment)
+            MESSAGE
+          end
+        end
+
+        context 'and the blobs association is invalid' do
+          it 'matches' do
+            record = record_having_one_attached(:avatar, invalidate_blobs: true)
+            expect { have_one_attached(:avatar) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_one_attached called avatar, but this could not be proved.
+  Expected User to have a has_one association called avatar_blob through avatar_attachment (avatar_blob should resolve to ActiveStorage::Blob for class_name)
+            MESSAGE
+          end
+        end
+
+        context 'and the eager loading scope does not exist' do
+          it 'matches' do
+            record = record_having_one_attached(:avatar, remove_eager_loading_scope: true)
+            expect { have_one_attached(:avatar) }.
+              not_to match_against(record).
+              and_fail_with <<-MESSAGE
+Expected User to have a has_one_attached called avatar, but this could not be proved.
+  User does not have a :with_attached_avatar scope.
+            MESSAGE
+          end
+        end
+      end
+    end
+
+    describe 'have_many_attached' do
+      describe '#description' do
+        it 'returns the message with the name of the association' do
+          matcher = have_many_attached(:avatars)
+          expect(matcher.description).
+            to eq('have a has_many_attached called avatars')
+        end
+      end
+
+      context 'when the attached exists on the model' do
+        it 'matches' do
+          record = record_having_many_attached(:avatars)
+          expect { have_many_attached(:avatars) }.
+            to match_against(record).
+            or_fail_with(<<-MESSAGE)
+Did not expect User to have a has_many_attached called avatars, but it does.
+          MESSAGE
+        end
+
+        context 'and the reader attribute does not exist' do
+          it 'matches' do
+            record = record_having_many_attached(:avatars, remove_reader: true)
+            expect { have_many_attached(:avatars) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_many_attached called avatars, but this could not be proved.
+  User does not have a :avatars method.
+            MESSAGE
+          end
+        end
+
+        context 'and the writer attribute does not exist' do
+          it 'matches' do
+            record = record_having_many_attached(:avatars, remove_writer: true)
+            expect { have_many_attached(:avatars) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_many_attached called avatars, but this could not be proved.
+  User does not have a :avatars= method.
+            MESSAGE
+          end
+        end
+
+        context 'and the attachments association does not exist' do
+          it 'matches' do
+            record = record_having_many_attached(:avatars, remove_attachments: true)
+            expect { have_many_attached(:avatars) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_many_attached called avatars, but this could not be proved.
+  Expected User to have a has_many association called avatars_attachments (no association called avatars_attachments)
+            MESSAGE
+          end
+        end
+
+        context 'and the blobs association is invalid' do
+          it 'matches' do
+            record = record_having_many_attached(:avatars, invalidate_blobs: true)
+            expect { have_many_attached(:avatars) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_many_attached called avatars, but this could not be proved.
+  Expected User to have a has_many association called avatars_blobs through avatars_attachments (avatars_blobs should resolve to ActiveStorage::Blob for class_name)
+            MESSAGE
+          end
+        end
+
+        context 'and the eager loading scope does not exist' do
+          it 'matches' do
+            record = record_having_many_attached(:avatars, remove_eager_loading_scope: true)
+            expect { have_many_attached(:avatars) }.
+              not_to match_against(record).
+              and_fail_with(<<-MESSAGE)
+Expected User to have a has_many_attached called avatars, but this could not be proved.
+  User does not have a :with_attached_avatars scope.
+            MESSAGE
+          end
+        end
+      end
+    end
+  end
+end
+
+def record_having_one_attached(
+  attached_name,
+  model_name: 'User',
+  remove_reader: false,
+  remove_writer: false,
+  remove_attachments: false,
+  invalidate_blobs: false,
+  remove_eager_loading_scope: false
+)
+  model = define_model(model_name) do
+    has_one_attached attached_name
+
+    if remove_reader
+      undef_method attached_name
+    end
+
+    if remove_writer
+      undef_method "#{attached_name}="
+    end
+
+    if remove_attachments
+      reflections.delete("#{attached_name}_attachment")
+    end
+
+    if invalidate_blobs
+      reflections["#{attached_name}_blob"].options[:class_name] = 'User'
+    end
+
+    if remove_eager_loading_scope
+      instance_eval <<-CODE, __FILE__, __LINE__ + 1
+undef with_attached_#{attached_name}
+      CODE
+    end
+  end
+
+  model.new
+end
+
+def record_having_many_attached(
+  attached_name,
+  model_name: 'User',
+  remove_reader: false,
+  remove_writer: false,
+  remove_attachments: false,
+  invalidate_blobs: false,
+  remove_eager_loading_scope: false
+)
+  model = define_model(model_name) do
+    has_many_attached attached_name
+
+    if remove_reader
+      undef_method attached_name
+    end
+
+    if remove_writer
+      undef_method "#{attached_name}="
+    end
+
+    if remove_attachments
+      reflections.delete("#{attached_name}_attachments")
+    end
+
+    if invalidate_blobs
+      reflections["#{attached_name}_blobs"].options[:class_name] = 'User'
+    end
+
+    if remove_eager_loading_scope
+      instance_eval <<-CODE, __FILE__, __LINE__ + 1
+undef with_attached_#{attached_name}
+      CODE
+    end
+  end
+
+  model.new
+end