Match has_one direction before deleting rel (#1662)

* Match has_one direction before deleting rel

When relationship_corresponding_rel matches on the rel class name,
it stops on the first match, ignoring the direction parameter.

When target_class represents the to_node, direction is :in.

When the relationship is a has_one/has_many between a pair
of nodes of the same class, the match could find and return
the to_node's :out association first, causing
delete_reverse_has_one_relationship() to delete it.

Checking the direction first prevents that.

* Move shared_examples_for group into loop using it

per
#1662 (comment)

(cherry picked from commit ff2f8a5)

lib/active_graph/node/has_n.rb

@@ -253,8 +253,10 @@ def delete_has_one_rel!(rel)
 
     def relationship_corresponding_rel(relationship, direction, target_class)
       self.class.associations.find do |_key, assoc|
-        assoc.relationship_class_name == relationship.class.name ||
-          (assoc.relationship_type == relationship.type.to_sym && assoc.target_class == target_class && assoc.direction == direction)
+        assoc.direction == direction && (
+          assoc.relationship_class_name == relationship.class.name ||
+          (assoc.relationship_type == relationship.type.to_sym && assoc.target_class == target_class)
+        )
       end
     end
 

spec/e2e/relationship_spec.rb

@@ -589,4 +589,61 @@ class ActiveRelSpecTypesInheritedRelClass < ActiveRelSpecTypesAutomaticRelType
       end
     end
   end
+
+  context "between nodes of the same class" do
+    before(:each) do
+      clear_model_memory_caches
+
+      stub_node_class('NodeClass') do
+        has_one  :out, :parent,   rel_class: :IsParentOf
+        has_many :in,  :children, rel_class: :IsParentOf
+      end
+
+      stub_relationship_class('IsParentOf') do
+        from_class :NodeClass
+        to_class   :NodeClass
+      end
+
+      @gen0 = NodeClass.create
+      @gen1 = @gen2 = nil
+    end
+
+    after(:each) { [@gen0, @gen1, @gen2].compact.each(&:destroy) }
+
+    %i(all none).each do |uniqueness|
+      context "with creates_unique(:#{uniqueness})" do
+        before(:each) { IsParentOf.creates_unique uniqueness }
+
+        it "creates (gen1)-->(gen0)" do
+          @gen1 = NodeClass.create parent: @gen0
+
+          expect(@gen1.parent.id).to eq @gen0.id
+
+          expect(@gen0.children.count).to eq 1
+          expect(@gen0.children.first.id).to eq @gen1.id
+        end
+
+        context "given (gen1)-->(gen0)" do
+          before(:each) { @gen1 = NodeClass.create parent: @gen0 }
+
+          describe "#create (gen2)-->(gen1)" do
+            it "adds a new node and relationsihp without affecting (gen1)-->(gen0)" do
+              @gen2 = NodeClass.create parent: @gen1
+
+              expect(@gen2.parent.id).to eq @gen1.id
+
+              expect(@gen1.children.count).to eq 1
+              expect(@gen1.children.first.id).to eq @gen2.id
+
+              expect(@gen1.parent).to(be_present, "gen1 lost its parent")
+              expect(@gen1.parent.id).to eq @gen0.id
+
+              expect(@gen0.children.count).to eq 1
+              expect(@gen0.children.first.id).to eq @gen1.id
+            end
+          end
+        end
+      end
+    end
+  end
 end