DEV: Add spec for validation

spec/extensions/topic_extension_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class DummyTopic < Topic
+  include CustomWizardTopicExtension
+end
+
+describe DummyTopic, type: :model do
+  fab!(:category_with_wizard) do
+    Fabricate(:category, custom_fields: { create_topic_wizard: 'true' })
+  end
+  fab!(:category_without_wizard) { Fabricate(:category) }
+  fab!(:user) { Fabricate(:user) }
+
+  context 'when the category has a create_topic_wizard custom field' do
+    it 'does not allow creating a topic directly' do
+      topic = DummyTopic.new(user: user, category: category_with_wizard)
+      topic.valid?
+      expect(topic.errors[:base]).to include(
+        I18n.t('wizard.error_messages.wizard_replacing_composer')
+      )
+    end
+  end
+
+  context 'when the category does not have a create_topic_wizard custom field' do
+    it 'allows creating a topic directly' do
+      topic =
+        DummyTopic.new(
+          user: user,
+          category: category_without_wizard,
+          title: 'A valid topic title'
+        )
+      is_valid = topic.valid?
+      puts topic.errors.full_messages unless is_valid
+      expect(is_valid).to be_truthy
+    end
+  end
+end