Add test

app/helpers/avatars_helper.rb

@@ -21,7 +21,7 @@ module AvatarsHelper
 
   def mail_avatar_tag(user, size: 48, **options)
     if user.avatar.attached?
-      image_tag user_avatar_url(notification.creator), alt: notification.creator.name, class: "avatar", **options
+      image_tag user_avatar_url(user), alt: user.name, class: "avatar", **options
     else
       tag.span class: "avatar", style: "background-color: #{avatar_background_color(user)};" do
         user.initials

test/mailers/notification/bundle_mailer_test.rb

@@ -0,0 +1,44 @@
+require "test_helper"
+
+class Notification::BundleMailerTest < ActionMailer::TestCase
+  setup do
+    @user = users(:david)
+
+    @bundle = Notification::Bundle.create!(
+      user: @user,
+      starts_at: 1.hour.ago,
+      ends_at: 1.hour.from_now
+    )
+  end
+
+  test "renders avatar with initials in span when avatar is not attached" do
+    create_notification(@user)
+
+    email = Notification::BundleMailer.notification(@bundle)
+
+    assert_match /<span[^>]*class="avatar"[^>]*>/, email.html_part.body.to_s
+    assert_match /#{@user.initials}/, email.html_part.body.to_s
+    assert_match /style="background-color: #[A-F0-9]{6};?"/, email.html_part.body.to_s
+  end
+
+  test "renders avatar with external image URL when avatar is attached" do
+    @user.avatar.attach(
+      io: File.open(Rails.root.join("test", "fixtures", "files", "avatar.png")),
+      filename: "avatar.png",
+      content_type: "image/png"
+    )
+
+    create_notification(@user)
+
+    email = Notification::BundleMailer.notification(@bundle)
+
+    assert_match /<img[^>]*class="avatar"[^>]*>/, email.html_part.body.to_s
+    assert_match /<img[^>]*class="avatar"[^>]*src="[^"]*"/, email.html_part.body.to_s
+    assert_match /alt="#{@user.name}"/, email.html_part.body.to_s
+  end
+
+  private
+    def create_notification(user)
+      Notification.create!(user: user, creator: user, source: events(:logo_published), created_at: 30.minutes.ago)
+    end
+end