DEV: Add tests for `categories` setting (#50)

This commit improves the test coverage for the client side logic
surrounding the `categories` theme setting

spec/system/category_banners_spec.rb

@@ -6,7 +6,12 @@ RSpec.describe "Category Banners", type: :system do
   let!(:theme) { upload_theme_component }
   fab!(:category) { Fabricate(:category, description: "<p>this is some description</p>") }
   fab!(:category_subcategory) do
-    Fabricate(:category, parent_category: category, description: "some description", uploaded_logo: Fabricate(:upload))
+    Fabricate(
+      :category,
+      parent_category: category,
+      description: "some description",
+      uploaded_logo: Fabricate(:upload),
+    )
   end
   let(:category_banner) { PageObjects::Components::CategoryBanner.new(category) }
   let(:subcategory_banner) { PageObjects::Components::CategoryBanner.new(category_subcategory) }
@@ -19,6 +24,47 @@ RSpec.describe "Category Banners", type: :system do
     expect(category_banner).to have_description("this is some description")
   end
 
+  context "when `categories` setting has been set" do
+    it "displays category banner for category and its subcategory when target is set to `all`" do
+      theme.update_setting(:categories, "#{category.name}:all")
+      theme.save!
+
+      visit(category.url)
+
+      expect(category_banner).to be_visible
+
+      visit(category_subcategory.url)
+
+      expect(subcategory_banner).to be_visible
+    end
+
+    it "displays category banner only for root category when target is set to `no_sub`" do
+      theme.update_setting(:categories, "#{category.name}:no_sub")
+      theme.save!
+
+      visit(category.url)
+
+      expect(category_banner).to be_visible
+
+      visit(category_subcategory.url)
+
+      expect(subcategory_banner).to be_not_visible
+    end
+
+    it "displays category banner only for sub categories when target is set to `only_sub`" do
+      theme.update_setting(:categories, "#{category.name}:only_sub")
+      theme.save!
+
+      visit(category.url)
+
+      expect(category_banner).to be_not_visible
+
+      visit(category_subcategory.url)
+
+      expect(subcategory_banner).to be_visible
+    end
+  end
+
   it "does not display the category description when `show_description` setting is false" do
     theme.update_setting(:show_description, false)
     theme.save!