Rescue from invalid DFC catalog URLs

This mistake should be dealt with differently but I wanted to make sure
that a really invalid URL is handled well, too.

app/controllers/admin/dfc_product_imports_controller.rb

@@ -27,6 +27,9 @@ module Admin
           @enterprise.supplied_variants.linked_to(subject.semanticId)&.product
         ]
       end
+    rescue URI::InvalidURIError
+      flash[:error] = t ".invalid_url"
+      redirect_to admin_product_import_path
     rescue Faraday::Error,
            Addressable::URI::InvalidURIError,
            ActionController::ParameterMissing => e

config/locales/en.yml

@@ -862,6 +862,7 @@ en:
           one: "1 selected"
           other: "%{count} selected"
         import: Import
+        invalid_url: This catalog URL is not valid.
       import:
         title: "DFC product catalog import"
         imported_products: "Imported products:"

spec/system/admin/dfc_product_import_spec.rb

@@ -22,7 +22,15 @@ RSpec.describe "DFC Product Import" do
 
     # We are testing against our own catalog for now but we want to replace
     # this with the URL of another app when available.
+    # We also add a common mistake: copying the URL with an extra space.
     host = Rails.application.default_url_options[:host]
+    url = " http://#{host}/api/dfc/enterprises/#{enterprise.id}/catalog_items"
+    fill_in "catalog_url", with: url
+    select enterprise.name, from: "Create products for enterprise"
+    click_button "Preview"
+
+    expect(page).to have_content "This catalog URL is not valid"
+
     url = "http://#{host}/api/dfc/enterprises/#{enterprise.id}/catalog_items"
     fill_in "catalog_url", with: url
     select enterprise.name, from: "Create products for enterprise"