ray/test/runtest.py

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import os
import unittest
import ray
import numpy as np
import time
import shutil
import string
import sys
from collections import namedtuple

if sys.version_info >= (3, 0):
  from importlib import reload

import ray.test.test_functions as test_functions
import ray.array.remote as ra
import ray.array.distributed as da

def assert_equal(obj1, obj2):
  if type(obj1).__module__ == np.__name__ or type(obj2).__module__ == np.__name__:
    if (hasattr(obj1, "shape") and obj1.shape == ()) or (hasattr(obj2, "shape") and obj2.shape == ()):
      # This is a special case because currently np.testing.assert_equal fails
      # because we do not properly handle different numerical types.
      assert obj1 == obj2, "Objects {} and {} are different.".format(obj1, obj2)
    else:
      np.testing.assert_equal(obj1, obj2)
  elif hasattr(obj1, "__dict__") and hasattr(obj2, "__dict__"):
    special_keys = ["_pytype_"]
    assert set(list(obj1.__dict__.keys()) + special_keys) == set(list(obj2.__dict__.keys()) + special_keys), "Objects {} and {} are different.".format(obj1, obj2)
    for key in obj1.__dict__.keys():
      if key not in special_keys:
        assert_equal(obj1.__dict__[key], obj2.__dict__[key])
  elif type(obj1) is dict or type(obj2) is dict:
    assert_equal(obj1.keys(), obj2.keys())
    for key in obj1.keys():
      assert_equal(obj1[key], obj2[key])
  elif type(obj1) is list or type(obj2) is list:
    assert len(obj1) == len(obj2), "Objects {} and {} are lists with different lengths.".format(obj1, obj2)
    for i in range(len(obj1)):
      assert_equal(obj1[i], obj2[i])
  elif type(obj1) is tuple or type(obj2) is tuple:
    assert len(obj1) == len(obj2), "Objects {} and {} are tuples with different lengths.".format(obj1, obj2)
    for i in range(len(obj1)):
      assert_equal(obj1[i], obj2[i])
  elif ray.serialization.is_named_tuple(type(obj1)) or ray.serialization.is_named_tuple(type(obj2)):
    assert len(obj1) == len(obj2), "Objects {} and {} are named tuples with different lengths.".format(obj1, obj2)
    for i in range(len(obj1)):
      assert_equal(obj1[i], obj2[i])
  else:
    assert obj1 == obj2, "Objects {} and {} are different.".format(obj1, obj2)

if sys.version_info >= (3, 0):
  long_extras = [0, np.array([["hi", u"hi"], [1.3, 1]])]
else:
  long_extras = [long(0), np.array([["hi", u"hi"], [1.3, long(1)]])]

PRIMITIVE_OBJECTS = [0, 0.0, 0.9, 1 << 62, "a", string.printable, "\u262F",
                     u"hello world", u"\xff\xfe\x9c\x001\x000\x00", None, True,
                     False, [], (), {}, np.int8(3), np.int32(4), np.int64(5),
                     np.uint8(3), np.uint32(4), np.uint64(5), np.float32(1.9),
                     np.float64(1.9), np.zeros([100, 100]),
                     np.random.normal(size=[100, 100]), np.array(["hi", 3]),
                     np.array(["hi", 3], dtype=object)] + long_extras

COMPLEX_OBJECTS = [[[[[[[[[[[[[]]]]]]]]]]]],
                   {"obj{}".format(i): np.random.normal(size=[100, 100]) for i in range(10)},
                   #{(): {(): {(): {(): {(): {(): {(): {(): {(): {(): {(): {(): {}}}}}}}}}}}}},
                   ((((((((((),),),),),),),),),),
                   {"a": {"b": {"c": {"d": {}}}}}
                   ]

class Foo(object):
  def __init__(self):
    pass

class Bar(object):
  def __init__(self):
    for i, val in enumerate(PRIMITIVE_OBJECTS + COMPLEX_OBJECTS):
      setattr(self, "field{}".format(i), val)

class Baz(object):
  def __init__(self):
    self.foo = Foo()
    self.bar = Bar()
  def method(self, arg):
    pass

class Qux(object):
  def __init__(self):
    self.objs = [Foo(), Bar(), Baz()]

class SubQux(Qux):
  def __init__(self):
    Qux.__init__(self)

class CustomError(Exception):
  pass

Point = namedtuple("Point", ["x", "y"])
NamedTupleExample = namedtuple("Example", "field1, field2, field3, field4, field5")

CUSTOM_OBJECTS = [Exception("Test object."), CustomError(), Point(11, y=22),
                  Foo(), Bar(), Baz(), # Qux(), SubQux(),
                  NamedTupleExample(1, 1.0, "hi", np.zeros([3, 5]), [1, 2, 3])]

BASE_OBJECTS = PRIMITIVE_OBJECTS + COMPLEX_OBJECTS + CUSTOM_OBJECTS

LIST_OBJECTS = [[obj] for obj in BASE_OBJECTS]
TUPLE_OBJECTS = [(obj,) for obj in BASE_OBJECTS]
# The check that type(obj).__module__ != "numpy" should be unnecessary, but
# otherwise this seems to fail on Mac OS X on Travis.
DICT_OBJECTS = ([{obj: obj} for obj in PRIMITIVE_OBJECTS if obj.__hash__ is not None and type(obj).__module__ != "numpy"] +
# DICT_OBJECTS = ([{obj: obj} for obj in BASE_OBJECTS if obj.__hash__ is not None] +
                [{0: obj} for obj in BASE_OBJECTS])

RAY_TEST_OBJECTS = BASE_OBJECTS + LIST_OBJECTS + TUPLE_OBJECTS + DICT_OBJECTS

# Check that the correct version of cloudpickle is installed.
try:
  import cloudpickle
  cloudpickle.dumps(Point)
except AttributeError:
  cloudpickle_command = "sudo pip install --upgrade git+git://github.com/cloudpipe/cloudpickle.git@0d225a4695f1f65ae1cbb2e0bbc145e10167cce4"
  raise Exception("You have an older version of cloudpickle that is not able to serialize namedtuples. Try running \n\n{}\n\n".format(cloudpickle_command))

class SerializationTest(unittest.TestCase):

  def testRecursiveObjects(self):
    ray.init(start_ray_local=True, num_workers=0)

    class ClassA(object):
      pass

    ray.register_class(ClassA)

    # Make a list that contains itself.
    l = []
    l.append(l)
    # Make an object that contains itself as a field.
    a1 = ClassA()
    a1.field = a1
    # Make two objects that contain each other as fields.
    a2 = ClassA()
    a3 = ClassA()
    a2.field = a3
    a3.field = a2
    # Make a dictionary that contains itself.
    d1 = {}
    d1["key"] = d1
    # Create a list of recursive objects.
    recursive_objects = [l, a1, a2, a3, d1]

    # Check that exceptions are thrown when we serialize the recursive objects.
    for obj in recursive_objects:
      self.assertRaises(Exception, lambda : ray.put(obj))

    ray.worker.cleanup()

  def testPassingArgumentsByValue(self):
    ray.init(start_ray_local=True, num_workers=1)

    @ray.remote
    def f(x):
      return x

    ray.register_class(Exception)
    ray.register_class(CustomError)
    ray.register_class(Point)
    ray.register_class(Foo)
    ray.register_class(Bar)
    ray.register_class(Baz)
    ray.register_class(NamedTupleExample)

    # Check that we can pass arguments by value to remote functions and that
    # they are uncorrupted.
    for obj in RAY_TEST_OBJECTS:
      assert_equal(obj, ray.get(f.remote(obj)))

    ray.worker.cleanup()

class WorkerTest(unittest.TestCase):

  def testPutGet(self):
    ray.init(start_ray_local=True, num_workers=0)

    for i in range(100):
      value_before = i * 10 ** 6
      objectid = ray.put(value_before)
      value_after = ray.get(objectid)
      self.assertEqual(value_before, value_after)

    for i in range(100):
      value_before = i * 10 ** 6 * 1.0
      objectid = ray.put(value_before)
      value_after = ray.get(objectid)
      self.assertEqual(value_before, value_after)

    for i in range(100):
      value_before = "h" * i
      objectid = ray.put(value_before)
      value_after = ray.get(objectid)
      self.assertEqual(value_before, value_after)

    for i in range(100):
      value_before = [1] * i
      objectid = ray.put(value_before)
      value_after = ray.get(objectid)
      self.assertEqual(value_before, value_after)

    ray.worker.cleanup()

class APITest(unittest.TestCase):

  def testRegisterClass(self):
    ray.init(start_ray_local=True, num_workers=0)

    # Check that putting an object of a class that has not been registered
    # throws an exception.
    class TempClass(object):
      pass
    self.assertRaises(Exception, lambda : ray.put(Foo))
    # Check that registering a class that Ray cannot serialize efficiently
    # raises an exception.
    self.assertRaises(Exception, lambda : ray.register_class(type(True)))
    # Check that registering the same class with pickle works.
    ray.register_class(type(float), pickle=True)
    self.assertEqual(ray.get(ray.put(float)), float)

    ray.worker.cleanup()

  def testKeywordArgs(self):
    reload(test_functions)
    ray.init(start_ray_local=True, num_workers=1)

    x = test_functions.keyword_fct1.remote(1)
    self.assertEqual(ray.get(x), "1 hello")
    x = test_functions.keyword_fct1.remote(1, "hi")
    self.assertEqual(ray.get(x), "1 hi")
    x = test_functions.keyword_fct1.remote(1, b="world")
    self.assertEqual(ray.get(x), "1 world")

    x = test_functions.keyword_fct2.remote(a="w", b="hi")
    self.assertEqual(ray.get(x), "w hi")
    x = test_functions.keyword_fct2.remote(b="hi", a="w")
    self.assertEqual(ray.get(x), "w hi")
    x = test_functions.keyword_fct2.remote(a="w")
    self.assertEqual(ray.get(x), "w world")
    x = test_functions.keyword_fct2.remote(b="hi")
    self.assertEqual(ray.get(x), "hello hi")
    x = test_functions.keyword_fct2.remote("w")
    self.assertEqual(ray.get(x), "w world")
    x = test_functions.keyword_fct2.remote("w", "hi")
    self.assertEqual(ray.get(x), "w hi")

    x = test_functions.keyword_fct3.remote(0, 1, c="w", d="hi")
    self.assertEqual(ray.get(x), "0 1 w hi")
    x = test_functions.keyword_fct3.remote(0, 1, d="hi", c="w")
    self.assertEqual(ray.get(x), "0 1 w hi")
    x = test_functions.keyword_fct3.remote(0, 1, c="w")
    self.assertEqual(ray.get(x), "0 1 w world")
    x = test_functions.keyword_fct3.remote(0, 1, d="hi")
    self.assertEqual(ray.get(x), "0 1 hello hi")
    x = test_functions.keyword_fct3.remote(0, 1)
    self.assertEqual(ray.get(x), "0 1 hello world")

    ray.worker.cleanup()

  def testVariableNumberOfArgs(self):
    reload(test_functions)
    ray.init(start_ray_local=True, num_workers=1)

    x = test_functions.varargs_fct1.remote(0, 1, 2)
    self.assertEqual(ray.get(x), "0 1 2")
    x = test_functions.varargs_fct2.remote(0, 1, 2)
    self.assertEqual(ray.get(x), "1 2")

    self.assertTrue(test_functions.kwargs_exception_thrown)
    self.assertTrue(test_functions.varargs_and_kwargs_exception_thrown)

    ray.worker.cleanup()

  def testNoArgs(self):
    reload(test_functions)
    ray.init(start_ray_local=True, num_workers=1)

    ray.get(test_functions.no_op.remote())

    ray.worker.cleanup()

  def testDefiningRemoteFunctions(self):
    ray.init(start_ray_local=True, num_workers=3)

    # Test that we can define a remote function in the shell.
    @ray.remote
    def f(x):
      return x + 1
    self.assertEqual(ray.get(f.remote(0)), 1)

    # Test that we can redefine the remote function.
    @ray.remote
    def f(x):
      return x + 10
    while True:
      val = ray.get(f.remote(0))
      self.assertTrue(val in [1, 10])
      if val == 10:
        break
      else:
        print("Still using old definition of f, trying again.")

    # Test that we can close over plain old data.
    data = [np.zeros([3, 5]), (1, 2, "a"), [0.0, 1.0, 1 << 62], 1 << 60, {"a": np.zeros(3)}]
    @ray.remote
    def g():
      return data
    ray.get(g.remote())

    # Test that we can close over modules.
    @ray.remote
    def h():
      return np.zeros([3, 5])
    assert_equal(ray.get(h.remote()), np.zeros([3, 5]))
    @ray.remote
    def j():
      return time.time()
    ray.get(j.remote())

    # Test that we can define remote functions that call other remote functions.
    @ray.remote
    def k(x):
      return x + 1
    @ray.remote
    def l(x):
      return ray.get(k.remote(x))
    @ray.remote
    def m(x):
      return ray.get(l.remote(x))
    self.assertEqual(ray.get(k.remote(1)), 2)
    self.assertEqual(ray.get(l.remote(1)), 2)
    self.assertEqual(ray.get(m.remote(1)), 2)

    ray.worker.cleanup()

  def testGetMultiple(self):
    ray.init(start_ray_local=True, num_workers=0)
    object_ids = [ray.put(i) for i in range(10)]
    self.assertEqual(ray.get(object_ids), list(range(10)))
    ray.worker.cleanup()

  def testWait(self):
    ray.init(start_ray_local=True, num_workers=1)

    @ray.remote
    def f(delay):
      time.sleep(delay)
      return 1

    objectids = [f.remote(1.0), f.remote(0.5), f.remote(0.5), f.remote(0.5)]
    ready_ids, remaining_ids = ray.wait(objectids)
    self.assertEqual(len(ready_ids), 1)
    self.assertEqual(len(remaining_ids), 3)
    ready_ids, remaining_ids = ray.wait(objectids, num_returns=4)
    self.assertEqual(set(ready_ids), set(objectids))
    self.assertEqual(remaining_ids, [])

    objectids = [f.remote(0.5), f.remote(0.5), f.remote(0.5), f.remote(0.5)]
    start_time = time.time()
    ready_ids, remaining_ids = ray.wait(objectids, timeout=1750, num_returns=4)
    self.assertLess(time.time() - start_time, 2)
    self.assertEqual(len(ready_ids), 3)
    self.assertEqual(len(remaining_ids), 1)
    ray.wait(objectids)
    objectids = [f.remote(1.0), f.remote(0.5), f.remote(0.5), f.remote(0.5)]
    start_time = time.time()
    ready_ids, remaining_ids = ray.wait(objectids, timeout=5000)
    self.assertTrue(time.time() - start_time < 5)
    self.assertEqual(len(ready_ids), 1)
    self.assertEqual(len(remaining_ids), 3)

    ray.worker.cleanup()

  def testCachingReusables(self):
    # Test that we can define reusable variables before the driver is connected.
    def foo_initializer():
      return 1
    def bar_initializer():
      return []
    def bar_reinitializer(bar):
      return []
    ray.reusables.foo = ray.Reusable(foo_initializer)
    ray.reusables.bar = ray.Reusable(bar_initializer, bar_reinitializer)

    @ray.remote
    def use_foo():
      return ray.reusables.foo
    @ray.remote
    def use_bar():
      ray.reusables.bar.append(1)
      return ray.reusables.bar

    ray.init(start_ray_local=True, num_workers=2)

    self.assertEqual(ray.get(use_foo.remote()), 1)
    self.assertEqual(ray.get(use_foo.remote()), 1)
    self.assertEqual(ray.get(use_bar.remote()), [1])
    self.assertEqual(ray.get(use_bar.remote()), [1])

    ray.worker.cleanup()

  def testCachingFunctionsToRun(self):
    # Test that we export functions to run on all workers before the driver is connected.
    def f(worker_info):
      sys.path.append(1)
    ray.worker.global_worker.run_function_on_all_workers(f)
    def f(worker_info):
      sys.path.append(2)
    ray.worker.global_worker.run_function_on_all_workers(f)
    def g(worker_info):
      sys.path.append(3)
    ray.worker.global_worker.run_function_on_all_workers(g)
    def f(worker_info):
      sys.path.append(4)
    ray.worker.global_worker.run_function_on_all_workers(f)

    ray.init(start_ray_local=True, num_workers=2)

    @ray.remote
    def get_state():
      time.sleep(1)
      return sys.path[-4], sys.path[-3], sys.path[-2], sys.path[-1]

    res1 = get_state.remote()
    res2 = get_state.remote()
    self.assertEqual(ray.get(res1), (1, 2, 3, 4))
    self.assertEqual(ray.get(res2), (1, 2, 3, 4))

    # Clean up the path on the workers.
    def f(worker_info):
      sys.path.pop()
      sys.path.pop()
      sys.path.pop()
      sys.path.pop()
    ray.worker.global_worker.run_function_on_all_workers(f)

    ray.worker.cleanup()

  def testRunningFunctionOnAllWorkers(self):
    ray.init(start_ray_local=True, num_workers=1)

    def f(worker_info):
      sys.path.append("fake_directory")
    ray.worker.global_worker.run_function_on_all_workers(f)
    @ray.remote
    def get_path1():
      return sys.path
    self.assertEqual("fake_directory", ray.get(get_path1.remote())[-1])
    def f(worker_info):
      sys.path.pop(-1)
    ray.worker.global_worker.run_function_on_all_workers(f)
    # Create a second remote function to guarantee that when we call
    # get_path2.remote(), the second function to run will have been run on the
    # worker.
    @ray.remote
    def get_path2():
      return sys.path
    self.assertTrue("fake_directory" not in ray.get(get_path2.remote()))

    ray.worker.cleanup()

  def testPassingInfoToAllWorkers(self):
    ray.init(start_ray_local=True, num_workers=10)

    def f(worker_info):
      sys.path.append(worker_info)
    ray.worker.global_worker.run_function_on_all_workers(f)
    @ray.remote
    def get_path():
      time.sleep(1)
      return sys.path
    # Retrieve the values that we stored in the worker paths.
    paths = ray.get([get_path.remote() for _ in range(10)])
    # Add the driver's path to the list.
    paths.append(sys.path)
    worker_infos = [path[-1] for path in paths]
    for worker_info in worker_infos:
      self.assertEqual(list(worker_info.keys()), ["counter"])
    counters = [worker_info["counter"] for worker_info in worker_infos]
    # We use range(11) because the driver also runs the function.
    self.assertEqual(set(counters), set(range(11)))
    # Clean up the worker paths.
    def f(worker_info):
      sys.path.pop(-1)
    ray.worker.global_worker.run_function_on_all_workers(f)

    ray.worker.cleanup()

  def testLoggingAPI(self):
    ray.init(start_ray_local=True, num_workers=1)

    def events():
      # This is a hack for getting the event log. It is not part of the API.
      keys = ray.worker.global_worker.redis_client.keys("event_log:*")
      return [ray.worker.global_worker.redis_client.lrange(key, 0, -1) for key in keys]

    def wait_for_num_events(num_events, timeout=10):
      start_time = time.time()
      while time.time() - start_time < timeout:
        if len(events()) >= num_events:
          return
        time.sleep(0.1)
      print("Timing out of wait.")

    @ray.remote
    def test_log_event():
      ray.log_event("event_type1", contents={"key": "val"})

    @ray.remote
    def test_log_span():
      with ray.log_span("event_type2", contents={"key": "val"}):
        pass

    # Make sure that we can call ray.log_event in a remote function.
    ray.get(test_log_event.remote())
    # Wait for the event to appear in the event log.
    wait_for_num_events(1)
    self.assertEqual(len(events()), 1)

    # Make sure that we can call ray.log_span in a remote function.
    ray.get(test_log_span.remote())
    # Wait for the events to appear in the event log.
    wait_for_num_events(2)
    self.assertEqual(len(events()), 2)

    @ray.remote
    def test_log_span_exception():
      with ray.log_span("event_type2", contents={"key": "val"}):
        raise Exception("This failed.")

    # Make sure that logging a span works if an exception is thrown.
    test_log_span_exception.remote()
    # Wait for the events to appear in the event log.
    wait_for_num_events(3)
    self.assertEqual(len(events()), 3)

    ray.worker.cleanup()

class PythonModeTest(unittest.TestCase):

  def testPythonMode(self):
    reload(test_functions)
    ray.init(start_ray_local=True, driver_mode=ray.PYTHON_MODE)

    @ray.remote
    def f():
      return np.ones([3, 4, 5])
    xref = f.remote()
    assert_equal(xref, np.ones([3, 4, 5])) # remote functions should return by value
    assert_equal(xref, ray.get(xref)) # ray.get should be the identity
    y = np.random.normal(size=[11, 12])
    assert_equal(y, ray.put(y)) # ray.put should be the identity

    # make sure objects are immutable, this example is why we need to copy
    # arguments before passing them into remote functions in python mode
    aref = test_functions.python_mode_f.remote()
    assert_equal(aref, np.array([0, 0]))
    bref = test_functions.python_mode_g.remote(aref)
    assert_equal(aref, np.array([0, 0])) # python_mode_g should not mutate aref
    assert_equal(bref, np.array([1, 0]))

    ray.worker.cleanup()

  def testReusableVariablesInPythonMode(self):
    reload(test_functions)
    ray.init(start_ray_local=True, driver_mode=ray.PYTHON_MODE)

    def l_init():
      return []
    def l_reinit(l):
      return []
    ray.reusables.l = ray.Reusable(l_init, l_reinit)

    @ray.remote
    def use_l():
      l = ray.reusables.l
      l.append(1)
      return l

    # Get the local copy of the reusable variable. This should be stateful.
    l = ray.reusables.l
    assert_equal(l, [])

    # Make sure the remote function does what we expect.
    assert_equal(ray.get(use_l.remote()), [1])
    assert_equal(ray.get(use_l.remote()), [1])

    # Make sure the local copy of the reusable variable has not been mutated.
    assert_equal(l, [])
    l = ray.reusables.l
    assert_equal(l, [])

    # Make sure that running a remote function does not reset the state of the
    # local copy of the reusable variable.
    l.append(2)
    assert_equal(ray.get(use_l.remote()), [1])
    assert_equal(l, [2])

    ray.worker.cleanup()

class ReusablesTest(unittest.TestCase):

  def testReusables(self):
    ray.init(start_ray_local=True, num_workers=1)

    # Test that we can add a variable to the key-value store.

    def foo_initializer():
      return 1
    def foo_reinitializer(foo):
      return foo

    ray.reusables.foo = ray.Reusable(foo_initializer, foo_reinitializer)
    self.assertEqual(ray.reusables.foo, 1)

    @ray.remote
    def use_foo():
      return ray.reusables.foo
    self.assertEqual(ray.get(use_foo.remote()), 1)
    self.assertEqual(ray.get(use_foo.remote()), 1)
    self.assertEqual(ray.get(use_foo.remote()), 1)

    # Test that we can add a variable to the key-value store, mutate it, and reset it.

    def bar_initializer():
      return [1, 2, 3]

    ray.reusables.bar = ray.Reusable(bar_initializer)

    @ray.remote
    def use_bar():
      ray.reusables.bar.append(4)
      return ray.reusables.bar
    self.assertEqual(ray.get(use_bar.remote()), [1, 2, 3, 4])
    self.assertEqual(ray.get(use_bar.remote()), [1, 2, 3, 4])
    self.assertEqual(ray.get(use_bar.remote()), [1, 2, 3, 4])

    # Test that we can use the reinitializer.

    def baz_initializer():
      return np.zeros([4])
    def baz_reinitializer(baz):
      for i in range(len(baz)):
        baz[i] = 0
      return baz

    ray.reusables.baz = ray.Reusable(baz_initializer, baz_reinitializer)

    @ray.remote
    def use_baz(i):
      baz = ray.reusables.baz
      baz[i] = 1
      return baz
    assert_equal(ray.get(use_baz.remote(0)), np.array([1, 0, 0, 0]))
    assert_equal(ray.get(use_baz.remote(1)), np.array([0, 1, 0, 0]))
    assert_equal(ray.get(use_baz.remote(2)), np.array([0, 0, 1, 0]))
    assert_equal(ray.get(use_baz.remote(3)), np.array([0, 0, 0, 1]))

    # Make sure the reinitializer is actually getting called. Note that this is
    # not the correct usage of a reinitializer because it does not reset qux to
    # its original state. This is just for testing.

    def qux_initializer():
      return 0
    def qux_reinitializer(x):
      return x + 1

    ray.reusables.qux = ray.Reusable(qux_initializer, qux_reinitializer)

    @ray.remote
    def use_qux():
      return ray.reusables.qux
    self.assertEqual(ray.get(use_qux.remote()), 0)
    self.assertEqual(ray.get(use_qux.remote()), 1)
    self.assertEqual(ray.get(use_qux.remote()), 2)

    ray.worker.cleanup()

  def testUsingReusablesOnDriver(self):
    ray.init(start_ray_local=True, num_workers=1)

    # Test that we can add a variable to the key-value store.

    def foo_initializer():
      return []
    def foo_reinitializer(foo):
      return []

    ray.reusables.foo = ray.Reusable(foo_initializer, foo_reinitializer)

    @ray.remote
    def use_foo():
      foo = ray.reusables.foo
      foo.append(1)
      return foo

    # Check that running a remote function does not reset the reusable variable
    # on the driver.
    foo = ray.reusables.foo
    self.assertEqual(foo, [])
    foo.append(2)
    self.assertEqual(foo, [2])
    foo.append(3)
    self.assertEqual(foo, [2, 3])

    self.assertEqual(ray.get(use_foo.remote()), [1])
    self.assertEqual(ray.get(use_foo.remote()), [1])
    self.assertEqual(ray.get(use_foo.remote()), [1])

    # Check that the copy of foo on the driver has not changed.
    self.assertEqual(foo, [2, 3])
    foo = ray.reusables.foo
    self.assertEqual(foo, [2, 3])

    ray.worker.cleanup()

class UtilsTest(unittest.TestCase):

  def testCopyingDirectory(self):
    # The functionality being tested here is really multi-node functionality,
    # but this test just uses a single node.

    ray.init(start_ray_local=True, num_workers=1)

    source_text = "hello world"

    temp_dir1 = os.path.join(os.path.dirname(__file__), "temp_dir1")
    source_dir = os.path.join(temp_dir1, "dir")
    source_file = os.path.join(source_dir, "file.txt")
    temp_dir2 = os.path.join(os.path.dirname(__file__), "temp_dir2")
    target_dir = os.path.join(temp_dir2, "dir")
    target_file = os.path.join(target_dir, "file.txt")

    def remove_temporary_files():
      if os.path.exists(temp_dir1):
        shutil.rmtree(temp_dir1)
      if os.path.exists(temp_dir2):
        shutil.rmtree(temp_dir2)

    # Remove the relevant files if they are left over from a previous run of
    # this test.
    remove_temporary_files()

    # Create the source files.
    os.mkdir(temp_dir1)
    os.mkdir(source_dir)
    with open(source_file, "w") as f:
      f.write(source_text)

    # Copy the source directory to the target directory.
    ray.experimental.copy_directory(source_dir, target_dir)
    time.sleep(0.5)

    # Check that the target files exist and are the same as the source files.
    self.assertTrue(os.path.exists(target_dir))
    self.assertTrue(os.path.exists(target_file))
    with open(target_file, "r") as f:
      self.assertEqual(f.read(), source_text)

    # Remove the relevant files to clean up.
    remove_temporary_files()

    ray.worker.cleanup()

if __name__ == "__main__":
  unittest.main(verbosity=2)