Serialize an Elixir pid

I was wondering how to serialize/deserialize a pid for some tricks with Ecto Sandbox and I found out some nice code on phoenix_ecto code. Here it goes my version:

defmodule MyApp.Serializer do
  @spec serialize(term) :: binary
  def serialize(term) do
    term
    |> :erlang.term_to_binary()
    |> Base.url_encode64()
  end

  @spec deserialize(binary) :: term
  def deserialize(str) when is_binary(str) do
    str
    |> Base.url_decode64!()
    |> :erlang.binary_to_term()
  end
end

And the test:

defmodule MyApp.SerializerTest do
  use ExUnit.Case, async: true

  alias MyApp.Serializer

  describe "serialize/1" do
    test "serializes a pid" do
      pid = self()
      assert pid |> Serializer.serialize() |> is_binary()
    end

    test "serializes a map" do
      map = %{foo: :bar}
      assert map |> Serializer.serialize() |> is_binary()
    end
  end

  describe "serialize/1, deserialize/1" do
    test "serializes and deserializes a pid" do
      pid = self()
      assert pid |> Serializer.serialize() |> Serializer.deserialize() == pid
    end

    test "serializes and deserializes a map" do
      map = %{foo: :bar}
      assert map |> Serializer.serialize() |> Serializer.deserialize() == map
    end
  end
end