Ensure list when converting to lazy (#3934)

Closes #3927.

Author: SteffenDE

lib/phoenix_live_view/test/dom.ex

@@ -146,7 +146,7 @@ defmodule Phoenix.LiveViewTest.DOM do
   @doc """
   Turns a tree into a lazy.
   """
-  def to_lazy(tree), do: LazyHTML.from_tree(tree)
+  def to_lazy(tree), do: LazyHTML.from_tree(List.wrap(tree))
 
   @doc """
   Escapes a string for use as a CSS identifier.

test/phoenix_live_view/integrations/elements_test.exs

@@ -457,6 +457,13 @@ defmodule Phoenix.LiveView.ElementsTest do
     assert from_element.meta.submitter == from_selector.meta.submitter
   end
 
+  test "put_submitter/2 works on forms without IDs", %{live: view} do
+    view
+    |> element("form[data-name='form-without-id']")
+    |> put_submitter("[name=button]")
+    |> render_submit()
+  end
+
   describe "render_submit" do
     test "raises if element is not a form", %{live: view} do
       assert_raise ArgumentError, "phx-submit is only allowed in forms, got \"a\"", fn ->

test/support/live_views/elements.ex

@@ -234,6 +234,10 @@ defmodule Phoenix.LiveViewTest.Support.ElementsLive do
       <button name="button_no_value">Button No Value</button>
     </form>
 
+    <form data-name="form-without-id" phx-submit="form-submit">
+      <button name="button" type="submit">button</button>
+    </form>
+
     <form
       id="trigger-form-default"
       phx-submit="form-submit-trigger"