feat(custom-field): add join_description attribute for GDPR join-form labels

test/membership/custom_field_validation_test.exs

@@ -159,6 +159,61 @@ defmodule Mv.Membership.CustomFieldValidationTest do
     end
   end
 
+  describe "join_description" do
+    test "persists join_description when set", %{actor: actor} do
+      assert {:ok, custom_field} =
+               CustomField
+               |> Ash.Changeset.for_create(:create, %{
+                 name: "dsgvo_field",
+                 value_type: :boolean,
+                 join_description: "hereby I confirm the GDPR"
+               })
+               |> Ash.create(actor: actor)
+
+      assert custom_field.join_description == "hereby I confirm the GDPR"
+    end
+
+    test "defaults to nil when not given", %{actor: actor} do
+      assert {:ok, custom_field} =
+               CustomField
+               |> Ash.Changeset.for_create(:create, %{
+                 name: "no_join_desc",
+                 value_type: :boolean
+               })
+               |> Ash.create(actor: actor)
+
+      assert custom_field.join_description == nil
+    end
+
+    test "rejects join_description longer than 1000 characters", %{actor: actor} do
+      assert {:error, changeset} =
+               CustomField
+               |> Ash.Changeset.for_create(:create, %{
+                 name: "too_long_join_desc",
+                 value_type: :boolean,
+                 join_description: String.duplicate("a", 1001)
+               })
+               |> Ash.create(actor: actor)
+
+      assert [%{field: :join_description, message: message}] = changeset.errors
+      assert message =~ "max" or message =~ "length" or message =~ "1000"
+    end
+
+    test "is writable via the update action", %{actor: actor} do
+      {:ok, custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{name: "updatable", value_type: :boolean})
+        |> Ash.create(actor: actor)
+
+      assert {:ok, updated} =
+               custom_field
+               |> Ash.Changeset.for_update(:update, %{join_description: "Accept the GDPR"})
+               |> Ash.update(actor: actor)
+
+      assert updated.join_description == "Accept the GDPR"
+    end
+  end
+
   describe "name uniqueness" do
     test "rejects duplicate names", %{actor: actor} do
       assert {:ok, _} =