Add test for invalid address parameters

spec/controllers/solidus_paypal_braintree/transactions_controller_spec.rb

@@ -41,7 +41,7 @@
         expect(order.payments.first.amount).to eq 55
       end
 
-      context "and an address is provided" do
+      context "and a valid address is provided" do
         it "creates a new address" do
           # Creating the order also creates 3 addresses, we want to make sure
           # the transaction import only creates 1 new one
@@ -51,6 +51,19 @@
         end
       end
 
+      context "and an invalid address is provided" do
+        before { params[:transaction][:address_attributes][:city] = nil }
+
+        it "raises a validation error" do
+          expect { post_create }.to raise_error(
+            ActiveRecord::RecordInvalid,
+            "Validation failed: " \
+            "Billing address city can't be blank, " \
+            "Shipping address city can't be blank"
+          )
+        end
+      end
+
       context "and the transaction does not have an address" do
         before { params[:transaction].delete(:address_attributes) }