diff --git a/spec/factories/calculated_adjustment_factory.rb b/spec/factories/calculated_adjustment_factory.rb
index 50ae6f5fce..3e9c6f5cc2 100644
--- a/spec/factories/calculated_adjustment_factory.rb
+++ b/spec/factories/calculated_adjustment_factory.rb
@@ -1,12 +1,23 @@
-attach_per_item_trait = proc do
-  trait :per_item do
-    transient { amount 1 }
-    calculator { build(:calculator_per_item, preferred_amount: amount) }
+FactoryBot.define do
+  factory :calculator_flat_rate, class: Spree::Calculator::FlatRate do
+    preferred_amount { generate(:calculator_amount) }
   end
 end
 
 FactoryBot.modify do
-  factory :payment_method, &attach_per_item_trait
-  factory :shipping_method, &attach_per_item_trait
-  factory :enterprise_fee, &attach_per_item_trait
+  attach_calculator_traits = proc do
+    trait :flat_rate do
+      transient { amount 1 }
+      calculator { build(:calculator_flat_rate, preferred_amount: amount) }
+    end
+
+    trait :per_item do
+      transient { amount 1 }
+      calculator { build(:calculator_per_item, preferred_amount: amount) }
+    end
+  end
+
+  factory :payment_method, &attach_calculator_traits
+  factory :shipping_method, &attach_calculator_traits
+  factory :enterprise_fee, &attach_calculator_traits
 end