subject(:actual_object) { ... } it { is_expected.to eq(expected_object) } と subject(:actual_object) { ... } it { expect(actual_object).to eq(expected_object) } では挙動が異なるという話 上の方を actual_object と expected_object を同じ属性などを定義した状態で比較しようとすると、 Compared using equal?, which compares object identity, but expected and actual are not the same object. Use expect(actual).to eq(expected) if you don't care about o