diff --git a/spec/features/admin/reports_spec.rb b/spec/features/admin/reports_spec.rb
index 2f0dde6e40..72e8524ae5 100644
--- a/spec/features/admin/reports_spec.rb
+++ b/spec/features/admin/reports_spec.rb
@@ -394,8 +394,8 @@ feature '
       let!(:adj_shipping) { create(:adjustment, order: order1, adjustable: order1, label: "Shipping", originator: shipping_method, amount: 100.55) }
       let!(:adj_fee1) { create(:adjustment, order: order1, adjustable: order1, originator: enterprise_fee1, label: "Enterprise fee untaxed", amount: 10, included_tax: 0) }
       let!(:adj_fee2) { create(:adjustment, order: order1, adjustable: order1, originator: enterprise_fee2, label: "Enterprise fee taxed", amount: 20, included_tax: 2) }
-      let!(:adj_manual1) { create(:adjustment, order: order1, adjustable: order1, originator: nil, source: nil, label: "Manual adjustment", amount: 30, included_tax: 0) }
-      let!(:adj_manual2) { create(:adjustment, order: order1, adjustable: order1, originator: nil, source: nil, label: "Manual adjustment", amount: 40, included_tax: 3) }
+      let!(:adj_manual1) { create(:adjustment, order: order1, adjustable: order1, originator: nil, label: "Manual adjustment", amount: 30, included_tax: 0) }
+      let!(:adj_manual2) { create(:adjustment, order: order1, adjustable: order1, originator: nil, label: "Manual adjustment", amount: 40, included_tax: 3) }
 
       before do
         order1.update_attribute :email, 'customer@email.com'
diff --git a/spec/helpers/admin/orders_helper_spec.rb b/spec/helpers/admin/orders_helper_spec.rb
index 63357be422..721eb2e4fb 100644
--- a/spec/helpers/admin/orders_helper_spec.rb
+++ b/spec/helpers/admin/orders_helper_spec.rb
@@ -7,7 +7,7 @@ describe Admin::OrdersHelper, type: :helper do
     let(:order) { create(:order) }
 
     it "selects eligible adjustments" do
-      adjustment = create(:adjustment, order: order, adjustable: order, amount: 1, source: nil)
+      adjustment = create(:adjustment, order: order, adjustable: order, amount: 1)
 
       expect(helper.order_adjustments_for_display(order)).to eq [adjustment]
     end
diff --git a/spec/helpers/checkout_helper_spec.rb b/spec/helpers/checkout_helper_spec.rb
index 4bfdb1b43b..b9fe4f54c9 100644
--- a/spec/helpers/checkout_helper_spec.rb
+++ b/spec/helpers/checkout_helper_spec.rb
@@ -36,7 +36,7 @@ describe CheckoutHelper, type: :helper do
     let(:order) { create(:order_with_totals_and_distribution) }
     let(:enterprise_fee) { create(:enterprise_fee, amount: 123) }
     let!(:fee_adjustment) {
-      create(:adjustment, originator: enterprise_fee, adjustable: order, source: order,
+      create(:adjustment, originator: enterprise_fee, adjustable: order,
                           order: order)
     }
 
@@ -61,7 +61,7 @@ describe CheckoutHelper, type: :helper do
     context "with return authorization adjustments" do
       let!(:return_adjustment) {
         create(:adjustment, originator_type: 'Spree::ReturnAuthorization', adjustable: order,
-                            source: nil, order: order)
+                            order: order)
       }
 
       it "includes return adjustments" do
diff --git a/spec/lib/spree/core/calculated_adjustments_spec.rb b/spec/lib/spree/core/calculated_adjustments_spec.rb
index 3bece5db69..218ef63c92 100644
--- a/spec/lib/spree/core/calculated_adjustments_spec.rb
+++ b/spec/lib/spree/core/calculated_adjustments_spec.rb
@@ -25,16 +25,16 @@ describe Spree::Core::CalculatedAdjustments do
 
     it "should be associated with the target" do
       expect(target.adjustments).to receive(:create)
-      tax_rate.create_adjustment("foo", target, order)
+      tax_rate.create_adjustment("foo", target)
     end
 
     it "should be associated with the order" do
-      tax_rate.create_adjustment("foo", target, order)
+      tax_rate.create_adjustment("foo", target)
       expect(target.adjustments.first.order_id).to eq order.id
     end
 
     it "should have the correct originator and an amount derived from the calculator and supplied calculable" do
-      adjustment = tax_rate.create_adjustment("foo", target, order)
+      adjustment = tax_rate.create_adjustment("foo", target)
       expect(adjustment).not_to be_nil
       expect(adjustment.amount).to eq 10
       expect(adjustment.adjustable).to eq order
@@ -42,7 +42,7 @@ describe Spree::Core::CalculatedAdjustments do
     end
 
     it "should be mandatory if true is supplied for that parameter" do
-      adjustment = tax_rate.create_adjustment("foo", target, order, true)
+      adjustment = tax_rate.create_adjustment("foo", target, true)
       expect(adjustment).to be_mandatory
     end
 
@@ -50,7 +50,7 @@ describe Spree::Core::CalculatedAdjustments do
       before { allow(calculator).to receive_messages(compute: 0) }
 
       context "when adjustment is mandatory" do
-        before { tax_rate.create_adjustment("foo", target, order, true) }
+        before { tax_rate.create_adjustment("foo", target, true) }
 
         it "should create an adjustment" do
           expect(Spree::Adjustment.count).to eq 1
diff --git a/spec/models/enterprise_fee_spec.rb b/spec/models/enterprise_fee_spec.rb
index 11ca441912..33f5401b0b 100644
--- a/spec/models/enterprise_fee_spec.rb
+++ b/spec/models/enterprise_fee_spec.rb
@@ -129,7 +129,6 @@ describe EnterpriseFee do
       order = create(:order)
       tax_rate = create(:tax_rate, calculator: build(:calculator))
       order.adjustments.create({ amount: 12.34,
-                                 source: order,
                                  originator: tax_rate,
                                  state: 'closed',
                                  label: 'hello' })
diff --git a/spec/models/spree/adjustment_spec.rb b/spec/models/spree/adjustment_spec.rb
index 0dcd24afa4..d85fb3d3a3 100644
--- a/spec/models/spree/adjustment_spec.rb
+++ b/spec/models/spree/adjustment_spec.rb
@@ -8,7 +8,7 @@ module Spree
     let(:adjustment) { Spree::Adjustment.create(label: "Adjustment", amount: 5) }
 
     describe "scopes" do
-      let!(:arbitrary_adjustment) { create(:adjustment, source: nil, label: "Arbitrary") }
+      let!(:arbitrary_adjustment) { create(:adjustment, label: "Arbitrary") }
       let!(:return_authorization_adjustment) { create(:adjustment, originator: create(:return_authorization)) }
 
       it "returns return_authorization adjustments" do
@@ -529,8 +529,7 @@ module Spree
       describe "inclusive and additional scopes" do
         let(:included) { true }
         let(:adjustment) {
-          create(:adjustment, adjustable: order, source: order,
-                 originator: tax_rate, included: included)
+          create(:adjustment, adjustable: order, originator: tax_rate, included: included)
         }
 
         context "when tax is included in price" do
diff --git a/spec/models/spree/order_spec.rb b/spec/models/spree/order_spec.rb
index 6757d9da18..84153fd4d9 100644
--- a/spec/models/spree/order_spec.rb
+++ b/spec/models/spree/order_spec.rb
@@ -677,7 +677,7 @@ describe Spree::Order do
     before do
       create(:adjustment, adjustable: order, originator: enterprise_fee, label: "EF", amount: 123,
                           included_tax: 2, order: order)
-      create(:adjustment, adjustable: shipment, source: shipment, originator: shipping_tax_rate,
+      create(:adjustment, adjustable: shipment, originator: shipping_tax_rate,
                           amount: 10, order: order, state: "closed")
       order.update!
     end
diff --git a/spec/models/spree/shipment_spec.rb b/spec/models/spree/shipment_spec.rb
index 614711579f..559c7954bd 100644
--- a/spec/models/spree/shipment_spec.rb
+++ b/spec/models/spree/shipment_spec.rb
@@ -390,7 +390,7 @@ describe Spree::Shipment do
     it "should create adjustment when not present" do
       allow(shipment).to receive_messages(selected_shipping_rate_id: 1)
       expect(shipping_method).to receive(:create_adjustment).with(shipment.adjustment_label,
-                                                                  shipment, shipment, true, "open")
+                                                                  shipment, true, "open")
       shipment.__send__(:ensure_correct_adjustment)
     end
 
diff --git a/spec/services/order_tax_adjustments_fetcher_spec.rb b/spec/services/order_tax_adjustments_fetcher_spec.rb
index ba908dc83b..866927d39f 100644
--- a/spec/services/order_tax_adjustments_fetcher_spec.rb
+++ b/spec/services/order_tax_adjustments_fetcher_spec.rb
@@ -46,7 +46,7 @@ describe OrderTaxAdjustmentsFetcher do
     end
     let(:admin_adjustment) do
       create(:adjustment, order: order, amount: 50.0, included_tax: tax_rate25.compute_tax(50.0),
-                          source: nil, label: "Admin Adjustment")
+                          label: "Admin Adjustment")
     end
 
     let(:order_cycle) do
diff --git a/spec/services/paypal_items_builder_spec.rb b/spec/services/paypal_items_builder_spec.rb
index 86a6646878..13c6c16c0b 100644
--- a/spec/services/paypal_items_builder_spec.rb
+++ b/spec/services/paypal_items_builder_spec.rb
@@ -21,7 +21,7 @@ describe PaypalItemsBuilder do
   context "listing adjustments" do
     let!(:admin_adjustment) {
       create(:adjustment, label: "Admin Adjustment", order: order, adjustable: order,
-                          amount: 12, source: nil, originator: nil, state: "closed")
+                          amount: 12, originator: nil, state: "closed")
     }
     let!(:ineligible_adjustment) {
       create(:adjustment, label: "Ineligible Adjustment", order: order, adjustable: order,
@@ -47,9 +47,8 @@ describe PaypalItemsBuilder do
     }
     let!(:enterprise_fee) { create(:enterprise_fee) }
     let!(:line_item_enterprise_fee) {
-      create(:adjustment, label: "Line Item Fee", order: order, adjustable: order,
-                          amount: 91, originator: enterprise_fee, source: order.line_items.first,
-                          state: "closed")
+      create(:adjustment, label: "Line Item Fee", order: order, adjustable: order.line_items.first,
+                          amount: 91, originator: enterprise_fee, state: "closed")
     }
     let!(:order_enterprise_fee) {
       create(:adjustment, label: "Order Fee", order: order, adjustable: order,