diff --git a/test/membership/member_field_visibility_test.exs b/test/membership/member_field_visibility_test.exs
index 6bc04f6..47ab5bd 100644
--- a/test/membership/member_field_visibility_test.exs
+++ b/test/membership/member_field_visibility_test.exs
@@ -80,4 +80,72 @@ defmodule Mv.Membership.MemberFieldVisibilityTest do
       end)
     end
   end
+
+  describe "update_single_member_field_visibility/3" do
+    test "atomically updates a single field in member_field_visibility" do
+      {:ok, settings} = Mv.Membership.get_settings()
+      field_string = "street"
+
+      # Update single field
+      {:ok, updated_settings} =
+        Mv.Membership.update_single_member_field_visibility(
+          settings,
+          field: field_string,
+          show_in_overview: false
+        )
+
+      # Verify the field was updated
+      assert updated_settings.member_field_visibility[field_string] == false
+
+      # Verify other fields are not affected
+      other_fields =
+        Mv.Constants.member_fields()
+        |> Enum.reject(&(&1 == String.to_existing_atom(field_string)))
+
+      Enum.each(other_fields, fn field ->
+        field_string = Atom.to_string(field)
+        # Fields not explicitly set should default to true (except exit_date)
+        expected = if field == :exit_date, do: false, else: true
+
+        assert Map.get(updated_settings.member_field_visibility, field_string, expected) ==
+                 expected
+      end)
+    end
+
+    test "returns error for invalid field name" do
+      {:ok, settings} = Mv.Membership.get_settings()
+
+      assert {:error, %Ash.Error.Invalid{errors: [%{field: :member_field_visibility}]}} =
+               Mv.Membership.update_single_member_field_visibility(
+                 settings,
+                 field: "invalid_field",
+                 show_in_overview: false
+               )
+    end
+
+    test "handles concurrent updates atomically" do
+      {:ok, settings} = Mv.Membership.get_settings()
+      field1 = "street"
+      field2 = "house_number"
+
+      # Simulate concurrent updates by updating different fields
+      {:ok, updated1} =
+        Mv.Membership.update_single_member_field_visibility(
+          settings,
+          field: field1,
+          show_in_overview: false
+        )
+
+      {:ok, updated2} =
+        Mv.Membership.update_single_member_field_visibility(
+          updated1,
+          field: field2,
+          show_in_overview: true
+        )
+
+      # Both fields should be correctly updated
+      assert updated2.member_field_visibility[field1] == false
+      assert updated2.member_field_visibility[field2] == true
+    end
+  end
 end