- existing_user = create(:user)
- new_user = build(:user, :display_name => existing_user.display_name)
- assert_not new_user.save
- assert_includes new_user.errors[:display_name], "has already been taken"
+ create(:user, :display_name => "H\u{e9}nryIV")
+
+ %W[H\u{e9}nryIV he\u{301}nryiv H\u{c9}nry\u2163 he\u{301}nry\u2173].each do |name|
+ new_user = build(:user, :display_name => name)
+ assert_not new_user.save
+ assert_includes new_user.errors[:display_name], "has already been taken"
+ end