feat: Add support for foreign_type qualifier on AssociationMatcher (#1609)

* Add support for foreign_type

* fix: Small adjusments on `foreign_type` qualifier

---------

Co-authored-by: mswiszcz <[email protected]>

Author: matsales28

lib/shoulda/matchers/active_record/association_matcher.rb

@@ -144,6 +144,28 @@ module ActiveRecord
       #         with_foreign_key('country_id')
       #     end
       #
+      # ##### with_foreign_type
+      #
+      # Use `with_foreign_type` to test usage of the `:foreign_type` option.
+      #
+      #     class Visitor < ActiveRecord::Base
+      #       belongs_to :location, foreign_type: 'facility_type', polymorphic: true
+      #     end
+      #
+      #     # RSpec
+      #     RSpec.describe Visitor, type: :model do
+      #       it do
+      #         should belong_to(:location).
+      #           with_foreign_type('facility_type')
+      #       end
+      #     end
+      #
+      #     # Minitest (Shoulda)
+      #     class VisitorTest < ActiveSupport::TestCase
+      #       should belong_to(:location).
+      #         with_foreign_type('facility_type')
+      #     end
+      #
       # ##### dependent
       #
       # Use `dependent` to assert that the `:dependent` option was specified.
@@ -795,6 +817,24 @@ def have_delegated_type(name)
       #       should have_many(:worries).with_foreign_key('worrier_id')
       #     end
       #
+      # ##### with_foreign_type
+      #
+      # Use `with_foreign_type` to test usage of the `:foreign_type` option.
+      #
+      #     class Hotel < ActiveRecord::Base
+      #       has_many :visitors, foreign_key: 'facility_type', as: :location
+      #     end
+      #
+      #     # RSpec
+      #     RSpec.describe Hotel, type: :model do
+      #       it { should have_many(:visitors).with_foreign_type('facility_type') }
+      #     end
+      #
+      #     # Minitest (Shoulda)
+      #     class HotelTest < ActiveSupport::TestCase
+      #       should have_many(:visitors).with_foreign_type('facility_type')
+      #     end
+      #
       # ##### dependent
       #
       # Use `dependent` to assert that the `:dependent` option was specified.
@@ -1066,6 +1106,24 @@ def have_many(name)
       #       should have_one(:job).with_foreign_key('worker_id')
       #     end
       #
+      # ##### with_foreign_type
+      #
+      # Use `with_foreign_type` to test usage of the `:foreign_type` option.
+      #
+      #     class Hotel < ActiveRecord::Base
+      #       has_one :special_guest, foreign_type: 'facility_type', as: :location
+      #     end
+      #
+      #     # RSpec
+      #     RSpec.describe Hotel, type: :model do
+      #       it { should have_one(:special_guest).with_foreign_type('facility_type') }
+      #     end
+      #
+      #     # Minitest (Shoulda)
+      #     class HotelTest < ActiveSupport::TestCase
+      #       should have_one(:special_guest).with_foreign_type('facility_type')
+      #     end
+      #
       # ##### through
       #
       # Use `through` to test usage of the `:through` option. This asserts that
@@ -1433,6 +1491,11 @@ def with_foreign_key(foreign_key)
           self
         end
 
+        def with_foreign_type(foreign_type)
+          @options[:foreign_type] = foreign_type
+          self
+        end
+
         def with_primary_key(primary_key)
           @options[:primary_key] = primary_key
           self
@@ -1510,6 +1573,7 @@ def matches?(subject)
             macro_correct? &&
             validate_inverse_of_through_association &&
             (polymorphic? || class_exists?) &&
+            foreign_type_matches? &&
             foreign_key_exists? &&
             primary_key_exists? &&
             query_constraints_exists? &&
@@ -1617,14 +1681,24 @@ def validate_inverse_of_through_association
         end
 
         def macro_is_not_through?
-          macro == :belongs_to ||
-            ([:has_many, :has_one].include?(macro) && !through?)
+          macro == :belongs_to || has_association_not_through?
+        end
+
+        def has_association_not_through?
+          [:has_many, :has_one].include?(macro) && !through?
         end
 
         def foreign_key_exists?
           !(belongs_foreign_key_missing? || has_foreign_key_missing?)
         end
 
+        def foreign_type_matches?
+          !options.key?(:foreign_type) || (
+            !belongs_foreign_type_missing? &&
+            !has_foreign_type_missing?
+          )
+        end
+
         def primary_key_exists?
           !macro_is_not_through? || primary_key_correct?(model_class)
         end
@@ -1651,12 +1725,20 @@ def belongs_foreign_key_missing?
           macro == :belongs_to && !class_has_foreign_key?(model_class)
         end
 
+        def belongs_foreign_type_missing?
+          macro == :belongs_to && !class_has_foreign_type?(model_class)
+        end
+
         def has_foreign_key_missing?
-          [:has_many, :has_one].include?(macro) &&
-            !through? &&
+          has_association_not_through? &&
             !class_has_foreign_key?(associated_class)
         end
 
+        def has_foreign_type_missing?
+          has_association_not_through? &&
+            !class_has_foreign_type?(associated_class)
+        end
+
         def class_name_correct?
           if options.key?(:class_name)
             if option_verifier.correct_for_constant?(
@@ -1819,6 +1901,22 @@ def validate_foreign_key(klass)
           end
         end
 
+        def class_has_foreign_type?(klass)
+          if options.key?(:foreign_type) && !foreign_type_correct?
+            @missing = foreign_type_failure_message(
+              klass,
+              options[:foreign_type],
+            )
+
+            false
+          elsif !has_column?(klass, foreign_type)
+            @missing = foreign_type_failure_message(klass, foreign_type)
+            false
+          else
+            true
+          end
+        end
+
         def has_column?(klass, column)
           case column
           when Array
@@ -1835,10 +1933,21 @@ def foreign_key_correct?
           )
         end
 
+        def foreign_type_correct?
+          option_verifier.correct_for_string?(
+            :foreign_type,
+            options[:foreign_type],
+          )
+        end
+
         def foreign_key_failure_message(klass, foreign_key)
           "#{klass} does not have a #{foreign_key} foreign key."
         end
 
+        def foreign_type_failure_message(klass, foreign_type)
+          "#{klass} does not have a #{foreign_type} foreign type."
+        end
+
         def primary_key_correct?(klass)
           if options.key?(:primary_key)
             if option_verifier.correct_for_string?(
@@ -1881,6 +1990,14 @@ def foreign_key_reflection
           end
         end
 
+        def foreign_type
+          if [:has_one, :has_many].include?(macro)
+            reflection.type
+          else
+            reflection.foreign_type
+          end
+        end
+
         def submatchers_match?
           failing_submatchers.empty?
         end

lib/shoulda/matchers/active_record/association_matchers/model_reflector.rb

@@ -8,6 +8,7 @@ class ModelReflector
             :associated_class,
             :association_foreign_key,
             :foreign_key,
+            :foreign_type,
             :has_and_belongs_to_many_name,
             :join_table_name,
             :polymorphic?,

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

@@ -31,6 +31,17 @@
       expect(Child.new).to belong_to(:parent)
     end
 
+    it 'accepts an association with an existing custom foreign key and type' do
+      define_model :parent
+      define_model :child, ancestor_id: :integer, ancestor_type: :string do
+        belongs_to :parent, polymorphic: true, foreign_key: 'ancestor_id', foreign_type: 'ancestor_type'
+      end
+
+      expect(Child.new).to belong_to(:parent).
+        with_foreign_key(:ancestor_id).
+        with_foreign_type(:ancestor_type)
+    end
+
     it 'accepts an association using an existing custom primary key' do
       define_model :parent
       define_model :child, parent_id: :integer, custom_primary_key: :integer do
@@ -1176,6 +1187,18 @@ def belonging_to_non_existent_class(model_name, assoc_name, options = {})
       expect(Parent.new).to have_many(:children)
     end
 
+    it 'accepts an association with a nonstandard reverse foreign type, using :inverse_of' do
+      define_model :visitor, location_id: :integer, facility_type: :string do
+        belongs_to :location, foreign_type: :facility_type, inverse_of: :visitors, polymorphic: true
+      end
+
+      define_model :hotel do
+        has_many :visitors, inverse_of: :location, foreign_type: :facility_type, as: :location
+      end
+
+      expect(Hotel.new).to have_many(:visitors).with_foreign_type(:facility_type)
+    end
+
     it 'rejects an association with a nonstandard reverse foreign key, if :inverse_of is not correct' do
       define_model :child, mother_id: :integer do
         belongs_to :mother, inverse_of: :children, class_name: :Parent
@@ -1189,16 +1212,24 @@ def belonging_to_non_existent_class(model_name, assoc_name, options = {})
     end
 
     it 'accepts an association with a nonstandard foreign key, with reverse association turned off' do
-      define_model :child, ancestor_id: :integer do
-      end
-
+      define_model :child, ancestor_id: :integer
       define_model :parent do
         has_many :children, foreign_key: :ancestor_id, inverse_of: false
       end
 
       expect(Parent.new).to have_many(:children)
     end
 
+    it 'accepts an association with a nonstandard type, with reverse association turned off' do
+      define_model :visitor, location_id: :integer, facility_type: :string
+
+      define_model :hotel do
+        has_many :visitors, foreign_type: :facility_type, inverse_of: false, as: :location
+      end
+
+      expect(Hotel.new).to have_many(:visitors).with_foreign_type(:facility_type)
+    end
+
     describe 'strict_loading' do
       context 'when the application is configured with strict_loading disabled by default' do
         it 'accepts an association with a matching :strict_loading option' do
@@ -1655,6 +1686,21 @@ def having_many_non_existent_class(model_name, assoc_name, options = {})
       expect(Person.new).to have_one(:detail).with_foreign_key(:detailed_person_id)
     end
 
+    it 'accepts an association with an existing custom foreign type' do
+      define_model :profile, user_id: :integer, related_user_type: :string
+
+      define_model :admin do
+        has_one :profile, foreign_type: :related_user_type, as: :user
+      end
+
+      define_model :moderator do
+        has_one :profile, foreign_type: :related_user_type, as: :user
+      end
+
+      expect(Admin.new).to have_one(:profile).with_foreign_type(:related_user_type)
+      expect(Moderator.new).to have_one(:profile).with_foreign_type(:related_user_type)
+    end
+
     it 'accepts an association using an existing custom primary key' do
       define_model :detail, person_id: :integer
       define_model :person, custom_primary_key: :integer do