add tests for member deletion

test/accounts/user_member_deletion_test.exs

@@ -0,0 +1,88 @@
+defmodule Mv.Accounts.UserMemberDeletionTest do
+  @moduledoc """
+  Tests for ON DELETE SET NULL constraint on users.member_id.
+  When a member is deleted, the linked user should remain but with member_id set to NULL.
+  """
+  use Mv.DataCase, async: true
+  alias Mv.Accounts
+  alias Mv.Membership
+
+  describe "User remains when linked Member is deleted (ON DELETE SET NULL)" do
+    @valid_user_attrs %{
+      email: "test@example.com"
+    }
+
+    @valid_member_attrs %{
+      first_name: "John",
+      last_name: "Doe",
+      email: "john@example.com"
+    }
+
+    test "deleting a member sets the user's member_id to NULL" do
+      # Create a member
+      {:ok, member} = Membership.create_member(@valid_member_attrs)
+
+      # Create a user linked to the member
+      {:ok, user} =
+        Accounts.create_user(Map.put(@valid_user_attrs, :member, %{id: member.id}))
+
+      # Verify the relationship is established
+      {:ok, user_before_delete} = Ash.get(Mv.Accounts.User, user.id, load: [:member])
+      assert user_before_delete.member_id == member.id
+      assert user_before_delete.member.id == member.id
+
+      # Delete the member
+      :ok = Membership.destroy_member(member)
+
+      # Verify the user still exists but member_id is NULL
+      {:ok, user_after_delete} = Ash.get(Mv.Accounts.User, user.id, load: [:member])
+      assert user_after_delete.id == user.id
+      assert user_after_delete.member_id == nil
+      assert user_after_delete.member == nil
+    end
+
+    test "user can be linked to a new member after old member is deleted" do
+      # Create first member
+      {:ok, member1} = Membership.create_member(@valid_member_attrs)
+
+      # Create user linked to first member
+      {:ok, user} =
+        Accounts.create_user(Map.put(@valid_user_attrs, :member, %{id: member1.id}))
+
+      assert user.member_id == member1.id
+
+      # Delete first member
+      :ok = Membership.destroy_member(member1)
+
+      # Reload user from database to get updated member_id (should be NULL)
+      {:ok, user_after_delete} = Ash.get(Mv.Accounts.User, user.id)
+      assert user_after_delete.member_id == nil
+
+      # Create second member
+      {:ok, member2} =
+        Membership.create_member(%{
+          first_name: "Jane",
+          last_name: "Smith",
+          email: "jane@example.com"
+        })
+
+      # Link user to second member (use reloaded user)
+      {:ok, updated_user} = Accounts.update_user(user_after_delete, %{member: %{id: member2.id}})
+
+      # Verify new relationship
+      {:ok, final_user} = Ash.get(Mv.Accounts.User, updated_user.id, load: [:member])
+      assert final_user.member_id == member2.id
+      assert final_user.member.id == member2.id
+    end
+
+    test "member without linked user can be deleted normally" do
+      {:ok, member} = Membership.create_member(@valid_member_attrs)
+
+      # Delete member (no users linked)
+      assert :ok = Membership.destroy_member(member)
+
+      # Verify member is deleted
+      assert {:error, _} = Ash.get(Mv.Membership.Member, member.id)
+    end
+  end
+end