text: from zict import Func
  
  from . import utils_test
  
  
  def inc(x):
      return x + 1
  
  
  def dec(x):
      return x - 1
  
  
  def rotl(x):
      return x[1:] + x[:1]
  
  
  def rotr(x):
      return x[-1:] + x[:-1]
  
  
  def test_simple():
      d = dict()
      f = Func(inc, dec, d)
      f["x"] = 10
      assert f["x"] == 10
      assert d["x"] == 11
  
      assert "x" in f
      assert list(f) == ["x"]
      assert list(f.values()) == [10]
      assert list(f.items()) == [("x", 10)]
  
      assert all(s in str(f) for s in ["inc", "dec", "x", "Func"])
      assert all(s in repr(f) for s in ["inc", "dec", "x", "Func"])
  
      del f["x"]
      assert "x" not in d
  
  
  def test_mapping():
      """
      Test mapping interface for Func().
      """
      d = {}
      z = Func(rotl, rotr, d)
      utils_test.check_mapping(z)
      utils_test.check_closing(z)
  