Assing created_at to transaction_from when created.

lib/activerecord-bitemporal/bitemporal.rb

@@ -357,6 +357,8 @@ def _create_record(attribute_names = self.attribute_names)
         # 自身の `valid_from` を設定
         self.valid_from = valid_datetime || Time.current if self.valid_from == ActiveRecord::Bitemporal::DEFAULT_VALID_FROM
 
+        self.transaction_from = self.created_at if changes.key?("created_at")
+
         # アソシエーションの子に対して `valid_from` を設定
         # MEMO: cache が存在しない場合、 public_send(reflection.name) のタイミングで新しくアソシエーションオブジェクトが生成されるが
         # この時に何故か生成できずに落ちるケースがあるので cache しているアソシエーションに対してのみイテレーションする

spec/activerecord-bitemporal/bitemporal_spec.rb

@@ -9,14 +9,14 @@
   end
 
   describe ".create" do
-    let(:attributes) { {} }
-
     context "creating" do
+      let(:attributes) { {} }
       subject { -> { Employee.create!(name: "Tom", **attributes) } }
       it { is_expected.to change(Employee, :call_after_save_count).by(1) }
     end
 
     context "created" do
+      let(:attributes) { {} }
       subject { Employee.create!(name: "Tom", **attributes) }
 
       context "with `bitemporal_id`" do
@@ -56,6 +56,27 @@
         it { is_expected.to have_attributes(valid_from: time, valid_to:  Time.utc(9999, 12, 31).in_time_zone) }
       end
     end
+
+    context "with transaction_from, created_at" do
+      context "only transaction_from" do
+        let(:transaction_from) { "2019/01/01".to_time }
+        subject { Employee.create(transaction_from: transaction_from) }
+        it { is_expected.to have_attributes(transaction_from: transaction_from, created_at: transaction_from) }
+      end
+
+      context "only created_at" do
+        let(:created_at) { "2019/01/01".to_time }
+        subject { Employee.create(created_at: created_at) }
+        it { is_expected.to have_attributes(created_at: created_at, transaction_from: created_at) }
+      end
+
+      context "created_at and transaction_from" do
+        let(:created_at) { "2019/01/01".to_time }
+        let(:transaction_from) { "2019/08/01".to_time }
+        subject { Employee.create(transaction_from: transaction_from, created_at: created_at) }
+        it { is_expected.to have_attributes(created_at: created_at, transaction_from: created_at) }
+      end
+    end
   end
 
   describe ".find" do