Add test isolation utilities for async testing with EnforcerServer

lib/casbin/test_helper.ex

@@ -0,0 +1,62 @@
+defmodule Casbin.TestHelper do
+  @moduledoc """
+  Helper functions for testing with isolated enforcer instances in async tests.
+
+  Provides utilities to create unique enforcer names and manage test enforcer lifecycle.
+  """
+
+  alias Casbin.EnforcerSupervisor
+  alias Casbin.EnforcerServer
+
+  @doc """
+  Generates a unique enforcer name for isolated testing.
+  """
+  @spec unique_enforcer_name(String.t()) :: String.t()
+  def unique_enforcer_name(prefix \\ "") do
+    ref = inspect(make_ref()) |> String.replace(~r/[^a-zA-Z0-9]/, "_")
+    timestamp = System.system_time(:microsecond)
+    random = :rand.uniform(999_999)
+
+    prefix_part = if prefix != "", do: "#{prefix}_", else: ""
+    "test_enforcer_#{prefix_part}#{ref}_#{timestamp}_#{random}"
+  end
+
+  @doc """
+  Starts an enforcer process for testing.
+  """
+  @spec start_test_enforcer(String.t(), String.t()) ::
+          {:ok, pid()} | {:error, term()}
+  def start_test_enforcer(enforcer_name, config_file) do
+    EnforcerSupervisor.start_enforcer(enforcer_name, config_file)
+  end
+
+  @doc """
+  Cleans up a test enforcer by stopping its process and removing it from the ETS table.
+  """
+  @spec cleanup_test_enforcer(String.t()) :: :ok
+  def cleanup_test_enforcer(enforcer_name) do
+    # Stop the enforcer process if it exists
+    case Registry.lookup(Casbin.EnforcerRegistry, enforcer_name) do
+      [{pid, _}] ->
+        if Process.alive?(pid) do
+          DynamicSupervisor.terminate_child(EnforcerSupervisor, pid)
+        end
+
+      [] ->
+        :ok
+    end
+
+    # Remove from ETS table
+    :ets.delete(:enforcers_table, enforcer_name)
+
+    :ok
+  end
+
+  @doc """
+  Resets an enforcer to its initial state by reloading the configuration.
+  """
+  @spec reset_test_enforcer(String.t(), String.t()) :: :ok | {:error, term()}
+  def reset_test_enforcer(enforcer_name, config_file) do
+    EnforcerServer.reset_configuration(enforcer_name, config_file)
+  end
+end