Add spec for creating a payment from admin page

spec/requests/spree/admin/payments_spec.rb

@@ -10,6 +10,68 @@ RSpec.describe Spree::Admin::PaymentsController, type: :request do
     sign_in create(:admin_user)
   end
 
+  describe "POST /admin/orders/:order_number/payments.json" do
+    let(:params) do
+      {
+        payment: {
+          payment_method_id: payment_method.id, amount: order.total
+        }
+      }
+    end
+    let(:payment_method) do
+      create(:payment_method, distributors: [order.distributor])
+    end
+
+    it "creates a payment" do
+      expect {
+        post("/admin/orders/#{order.number}/payments.json", params:)
+      }.to change { order.payments.count }.by(1)
+    end
+
+    it "redirect to payments page" do
+      post("/admin/orders/#{order.number}/payments.json", params:)
+
+      expect(response).to redirect_to(spree.admin_order_payments_path(order))
+      expect(flash[:success]).to eq "Payment has been successfully created!"
+    end
+
+    context "when failing to create payment" do
+      it "redirects to payments page" do
+        payment_mock = instance_double(Spree::Payment)
+        allow(order.payments).to receive(:build).and_return(payment_mock)
+        allow(payment_mock).to receive(:save).and_return(false)
+
+        post("/admin/orders/#{order.number}/payments.json", params:)
+
+        expect(response).to redirect_to(spree.admin_order_payments_path(order))
+      end
+    end
+
+    context "when a getway error happens" do
+      let(:payment_method) do
+        create(:stripe_sca_payment_method, distributors: [order.distributor])
+      end
+
+      it "redirect to payments page" do
+        allow(Spree::Order).to receive(:find_by!).and_return(order)
+
+        stripe_sca_payment_authorize =
+          instance_double(OrderManagement::Order::StripeScaPaymentAuthorize)
+        allow(OrderManagement::Order::StripeScaPaymentAuthorize).to receive(:new)
+          .and_return(stripe_sca_payment_authorize)
+        # Simulate an error
+        allow(stripe_sca_payment_authorize).to receive(:call!) do
+          order.errors.add(:base, "authorization_failure")
+        end
+
+        post("/admin/orders/#{order.number}/payments.json", params:)
+
+        expect(response).to redirect_to(spree.admin_order_payments_path(order))
+        expect(flash[:error]).to eq("Authorization Failure")
+      end
+    end
+  end
+
   describe "PUT /admin/orders/:order_number/payments/:id/fire" do
     let(:payment) do
       create(