Refactor: Move to_form_data! to Field

What changed?
=============

We move `to_form_data!` from `FormData` to `Field` since it's field data
that's using it. We want to create a better `FormData` structure to
handle form data transformations, but for now, we make this refactor to
clean up where we're using FormData.

lib/phoenix_test/field.ex

@@ -80,4 +80,23 @@ defmodule PhoenixTest.Field do
       _ -> false
     end
   end
+
+  def to_form_data!(%{value: values} = field) when is_list(values) do
+    Enum.map(values, &{field.name, &1})
+  end
+
+  def to_form_data!(field) do
+    validate!(field)
+    [{field.name, field.value}]
+  end
+
+  defp validate!(field) do
+    if field.name == nil do
+      raise ArgumentError, """
+      Field is missing a `name` attribute:
+
+      #{Html.raw(field.parsed)}
+      """
+    end
+  end
 end

lib/phoenix_test/live.ex

@@ -8,7 +8,6 @@ defmodule PhoenixTest.Live do
   alias PhoenixTest.Field
   alias PhoenixTest.FileUpload
   alias PhoenixTest.Form
-  alias PhoenixTest.FormData
   alias PhoenixTest.Html
   alias PhoenixTest.Query
   alias PhoenixTest.Select
@@ -227,7 +226,7 @@ defmodule PhoenixTest.Live do
   end
 
   defp fill_in_field_data(session, field) do
-    new_form_data = FormData.to_form_data!(field)
+    new_form_data = Field.to_form_data!(field)
     form = Field.parent_form!(field)
 
     session =

lib/phoenix_test/static.ex

@@ -9,7 +9,6 @@ defmodule PhoenixTest.Static do
   alias PhoenixTest.Field
   alias PhoenixTest.FileUpload
   alias PhoenixTest.Form
-  alias PhoenixTest.FormData
   alias PhoenixTest.Html
   alias PhoenixTest.Link
   alias PhoenixTest.OpenBrowser
@@ -219,7 +218,7 @@ defmodule PhoenixTest.Static do
   end
 
   defp fill_in_field_data(session, field) do
-    new_form_data = FormData.to_form_data!(field)
+    new_form_data = Field.to_form_data!(field)
     form = Field.parent_form!(field)
 
     Map.update!(session, :active_form, fn active_form ->

test/phoenix_test/field_test.exs

@@ -184,4 +184,30 @@ defmodule PhoenixTest.FieldTest do
       refute Field.belongs_to_form?(field)
     end
   end
+
+  describe "to_form_data!" do
+    test "transforms a field into a name/value pair" do
+      html = """
+      <label for="name">Name</label>
+      <input id="name" type="text" name="name" value="Hello world"/>
+      """
+
+      field = Field.find_input!(html, "input", "Name", exact: true)
+
+      assert [{"name", "Hello world"}] = Field.to_form_data!(field)
+    end
+
+    test "raises error if name attribute is missing" do
+      html = """
+      <label for="name">Name</label>
+      <input id="name" type="text" value="Hello world"/>
+      """
+
+      field = Field.find_input!(html, "input", "Name", exact: true)
+
+      assert_raise ArgumentError, ~r/missing a `name`/, fn ->
+        Field.to_form_data!(field)
+      end
+    end
+  end
 end