diff --git a/spec/migrations/migrate_shipping_taxes_spec.rb b/spec/migrations/migrate_shipping_taxes_spec.rb
new file mode 100644
index 0000000000..fb625a385f
--- /dev/null
+++ b/spec/migrations/migrate_shipping_taxes_spec.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require_relative '../../db/migrate/20210224190247_migrate_shipping_taxes'
+
+describe MigrateShippingTaxes do
+  let(:migration) { MigrateShippingTaxes.new }
+
+  describe '#shipping_tax_category' do
+    it "creates a new shipping tax category" do
+      migration.shipping_tax_category
+
+      expect(Spree::TaxCategory.last.name).to eq I18n.t(:shipping)
+    end
+  end
+
+  describe '#create_shipping_tax_rates' do
+    let!(:zone1) { create(:zone_with_member) }
+    let!(:zone2) { create(:zone_with_member) }
+
+    before do
+      allow(migration).to receive(:instance_shipping_tax_rate) { 0.25 }
+    end
+
+    it "creates a shipping tax rate for each zone" do
+      migration.create_shipping_tax_rates
+
+      tax_rates = Spree::TaxRate.all
+
+      expect(tax_rates.count).to eq 2
+      expect(tax_rates.map(&:zone_id).uniq).to eq [zone1.id, zone2.id]
+      expect(tax_rates.map(&:amount).uniq).to eq [0.25]
+    end
+  end
+
+  describe '#assign_to_shipping_methods' do
+    let!(:shipping_method1) { create(:shipping_method) }
+    let!(:shipping_method2) { create(:shipping_method) }
+    let(:shipping_tax_category) { create(:tax_category) }
+
+    before do
+      allow(migration).to receive(:shipping_tax_category) { shipping_tax_category }
+    end
+
+    it "assigns the new shipping tax category to all shipping methods" do
+      migration.assign_to_shipping_methods
+
+      expect(shipping_method1.reload.tax_category).to eq shipping_tax_category
+      expect(shipping_method2.reload.tax_category).to eq shipping_tax_category
+    end
+  end
+
+  describe '#migrate_tax_amounts_to_adjustments' do
+    let!(:zone) { create(:zone_with_member) }
+    let!(:shipping_tax_category) { create(:tax_category) }
+    let!(:shipping_tax_rate) {
+      create(:tax_rate, zone: zone, tax_category: shipping_tax_category, name: "Shipping Tax Rate")
+    }
+    let(:order) { create(:completed_order_with_fees) }
+    let(:shipment) { order.shipment }
+
+    before do
+      shipment.adjustments.first.update_columns(included_tax: 0.23)
+      allow(order).to receive(:tax_zone) { zone }
+      allow(migration).to receive(:shipping_tax_category) { shipping_tax_category }
+    end
+
+    it "migrates the shipment's tax to a tax adjustment" do
+      expect(shipment.adjustments.first.included_tax).to eq 0.23
+      expect(shipment.included_tax_total).to be_zero
+      expect(shipment.adjustments.tax.count).to be_zero
+
+      migration.migrate_tax_amounts_to_adjustments
+
+      expect(shipment.reload.included_tax_total).to eq 0.23
+      expect(shipment.adjustments.tax.count).to eq 1
+
+      shipping_tax_adjustment = shipment.adjustments.tax.first
+
+      expect(shipping_tax_adjustment.amount).to eq 0.23
+      expect(shipping_tax_adjustment.originator).to eq shipping_tax_rate
+      expect(shipping_tax_adjustment.source).to eq shipment
+      expect(shipping_tax_adjustment.adjustable).to eq shipment
+      expect(shipping_tax_adjustment.order_id).to eq order.id
+      expect(shipping_tax_adjustment.included).to eq true
+      expect(shipping_tax_adjustment.state).to eq "closed"
+    end
+  end
+end