# Copyright 2020 DeepMind Technologies Limited. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Tests for jaxline's utils."""

import functools
import itertools as it
import time
from unittest import mock

from absl.testing import absltest
from absl.testing import flagsaver
import jax
import jax.numpy as jnp
from jaxline import utils
import numpy as np


class PyPrefetchTest(absltest.TestCase):

  def testEmpty(self):
    self.assertEqual(list(utils.py_prefetch(lambda: ())), [])

  def testBaseCase(self):
    self.assertEqual(list(utils.py_prefetch(lambda: range(100))),
                     list(range(100)))

  def testBadFunction(self):

    def _bad_function():
      raise ValueError

    iterable = utils.py_prefetch(_bad_function)
    with self.assertRaises(ValueError):
      next(iterable)

  def testBadFunctionIteration(self):

    def _bad_iterable():
      yield 1
      raise ValueError

    iterable = utils.py_prefetch(_bad_iterable)
    self.assertEqual(next(iterable), 1)
    with self.assertRaises(ValueError):
      next(iterable)


class TreePsumTest(absltest.TestCase):

  def testBaseCase(self):
    # pick leaf objects with leading dimension one as these tests will
    # be run on a single device.
    data = {"a": jnp.array([1]), "b": jnp.array([2])}
    data_summed = jax.pmap(
        lambda x: utils.tree_psum(x, axis_name="i"), axis_name="i")(data)
    self.assertEqual(data_summed, data)

  def testEmpty(self):
    data = {"a": jnp.array([]), "b": jnp.array([])}
    with self.assertRaises(ZeroDivisionError):
      jax.pmap(lambda x: utils.tree_psum(x, axis_name="i"), axis_name="i")(data)

  def testSingleLeafTree(self):
    data = jnp.array([1])
    data_summed = jax.pmap(
        lambda x: utils.tree_psum(x, axis_name="i"), axis_name="i")(data)
    self.assertEqual(data_summed, data)

  def testNotNumpy(self):
    data = [1]
    with self.assertRaises(ValueError):
      jax.pmap(lambda x: utils.tree_psum(x, axis_name="i"), axis_name="i")(data)

  def testNumDevicesMismatch(self):
    data = jnp.array([1, 2])  # assumes 2 devices but we only have 1
    with self.assertRaises(ValueError):
      jax.pmap(lambda x: utils.tree_psum(x, axis_name="i"), axis_name="i")(data)

  def testNoPmapWrapper(self):
    with self.assertRaises(NameError):  # axis_name will be undefined
      utils.tree_psum(jnp.array([1]), axis_name="i")

  def testAxisNameMismatch(self):
    data = jnp.array([1])
    with self.assertRaises(NameError):
      jax.pmap(lambda x: utils.tree_psum(x, axis_name="i"), axis_name="j")(data)


class MakeAsyncTest(absltest.TestCase):

  def testBaseCase(self):
    """Tests correct execution for single call."""
    r = []
    async_fn = utils.make_async()(lambda: r.append("a"))
    async_fn()
    time.sleep(1)
    self.assertListEqual(r, ["a"])

  def testNonBlocking(self):
    """Tests async function doesn't block the main thread."""
    r = []
    async_fn = utils.make_async()(lambda: r.append((time.sleep(5), "a")))
    r.append((None, "b"))
    async_fn().result()
    self.assertListEqual(r, [(None, "b"), (None, "a")])

  def testSerialExecution(self):
    """Tests multiple calls to async function execute serially."""
    r = []
    a = lambda: r.append((time.sleep(5), "a"))
    b = lambda: r.append((None, "b"))
    async_fn = utils.make_async()(lambda f: f())
    async_fn(a)
    async_fn(b).result()
    self.assertListEqual(r, [(None, "a"), (None, "b")])

  def testErrorOnNextCall(self):
    """Tests background thread error raised in main thread on next call."""

    @utils.make_async()
    def async_fn():
      raise ValueError()

    # First call will trigger an error in the background thread.
    async_fn()

    with self.assertRaises(ValueError):
      # Background thread error will be raised in the main thread on next call
      async_fn()

  def testSubsequentCallsDontRun(self):
    """Tests that subsequent calls don't run after an error has occurred."""

    runs = []

    @utils.make_async()
    def async_fn():
      runs.append(None)
      raise ValueError()

    # First call will trigger an error in the background thread.
    async_fn()

    for _ in range(2):
      with self.assertRaises(ValueError):
        # Background thread error will be raised in the main thread on
        # subsequent calls and _bad_function will not be run.
        async_fn()

    self.assertListEqual(runs, [None])

  def testErrorInBackgroundThread(self):
    """Tests background thread raises the error."""

    @utils.make_async()
    def async_fn():
      raise ValueError()

    future = async_fn()  # pylint: disable=assignment-from-no-return
    self.assertIsNotNone(future.exception())


class TestBroadcast(absltest.TestCase):

  def test_bcast_local_devices(self):
    self.assertEqual(utils.bcast_local_devices(jnp.zeros([])),
                     jnp.zeros([jax.local_device_count()]))

    self.assertEqual(utils.bcast_local_devices(jnp.ones([])),
                     jnp.ones([jax.local_device_count()]))

  def test_bcast_local_devices_empty_tree(self):
    self.assertIsNone(utils.bcast_local_devices(None))
    self.assertEqual(utils.bcast_local_devices({}), {})

  def test_bcast_local_devices_tree(self):
    num_devices = jax.local_device_count()
    tree = utils.bcast_local_devices({"ones": jnp.ones([]),
                                      "zeros": jnp.zeros([])})
    self.assertEqual(tree, {"ones": jnp.ones([num_devices]),
                            "zeros": jnp.zeros([num_devices])})


class TestLogActivity(absltest.TestCase):

  @mock.patch("jaxline.utils.logging.info")
  def test_log_success(self, mock_info):
    """Tests that logging an activity is successful."""

    with utils.log_activity("for test"):
      pass

    mock_info.assert_any_call("[jaxline] %s starting...", "for test")
    mock_info.assert_any_call("[jaxline] %s finished.", "for test")

  @mock.patch("absl.logging.exception")
  @mock.patch("absl.logging.info")
  def test_log_failure(self, mock_info, mock_exc):
    """Tests that an error thrown by an activity is correctly caught."""

    with self.assertRaisesRegex(ValueError, "Intentional"):
      with utils.log_activity("for test"):
        raise ValueError("Intentional")

    mock_info.assert_any_call("[jaxline] %s starting...", "for test")
    mock_exc.assert_any_call("[jaxline] %s failed with error.", "for test")


class TestSpecializeRngHostDevice(absltest.TestCase):

  @classmethod
  def setUpClass(cls):
    super(TestSpecializeRngHostDevice, cls).setUpClass()
    rng = jax.random.PRNGKey(0)
    cls.rng = jnp.broadcast_to(
        rng, (jax.local_device_count(),) + rng.shape)

  def test_unique_device(self):
    """Tests that rngs are unique across devices."""

    mode = "unique_host_unique_device"
    host_id_devices = utils.host_id_devices_for_rng(mode)
    specialize_func = jax.pmap(functools.partial(
        utils.specialize_rng_host_device, axis_name="i",
        mode=mode), axis_name="i")

    rng = specialize_func(self.rng, host_id_devices)

    self.assertEqual(
        np.unique(rng, axis=0).shape[0], jax.local_device_count())

  def test_same_device(self):
    """Tests rngs are same across devices."""

    mode = "unique_host_same_device"
    host_id_devices = utils.host_id_devices_for_rng(mode)
    specialize_func = jax.pmap(functools.partial(
        utils.specialize_rng_host_device, axis_name="i",
        mode=mode), axis_name="i")
    rng = specialize_func(self.rng, host_id_devices)

    self.assertEqual(
        np.unique(rng, axis=0).shape[0], 1)

  def test_unique_host(self):
    """Tests rngs unique between hosts."""

    mode = "unique_host_same_device"
    with mock.patch.object(utils.jax, "host_id", return_value=0):
      host_id_devices = utils.host_id_devices_for_rng(mode)
      specialize_func = jax.pmap(functools.partial(
          utils.specialize_rng_host_device, axis_name="i",
          mode=mode), axis_name="i")
      rng0 = specialize_func(self.rng, host_id_devices)
    with mock.patch.object(utils.jax, "host_id", return_value=1):
      host_id_devices = utils.host_id_devices_for_rng(mode)
      specialize_func = jax.pmap(functools.partial(
          utils.specialize_rng_host_device, axis_name="i",
          mode=mode), axis_name="i")
      rng1 = specialize_func(self.rng, host_id_devices)

    self.assertEqual(
        np.unique(np.concatenate([rng0, rng1], axis=0), axis=0).shape[0], 2)


class TestRendezvous(absltest.TestCase):

  def test_rendezvous(self):
    """Test that rendezvous doesn't fail."""

    utils.rendezvous()


class TestJaxlineDisablePmapJit(absltest.TestCase):

  @mock.patch.object(utils.chex, "fake_pmap_and_jit", autospec=True)
  def test_pmap_jit_disabled(self, mock_fake_pmap_and_jit):
    """Tests pmap/jit are disabled if --jaxline_disable_pmap_jit is set."""

    with self.subTest("PmapJitNotDisabled"):
      with flagsaver.flagsaver(jaxline_disable_pmap_jit=False):
        utils.disable_pmap_jit(lambda: None)()
        mock_fake_pmap_and_jit.assert_not_called()

    with self.subTest("PmapJitDisabled"):
      with flagsaver.flagsaver(jaxline_disable_pmap_jit=True):
        utils.disable_pmap_jit(lambda: None)()
        mock_fake_pmap_and_jit.assert_called_once()


class DoubleBufferTest(absltest.TestCase):

  def test_double_buffer(self):
    if jax.default_backend() != "gpu":
      self.skipTest("Only necessary on GPU.")

    n = jax.local_device_count()
    dataset = it.repeat(np.ones([n]))
    iterator = iter(utils.double_buffer(dataset))

    batch_ptrs = []
    while len(batch_ptrs) < 4:
      batch = next(iterator)
      ptrs = [b.unsafe_buffer_pointer() for b in batch.device_buffers]
      batch_ptrs.append(ptrs)
      del batch

    self.assertEqual(batch_ptrs[0], batch_ptrs[2])
    self.assertEqual(batch_ptrs[1], batch_ptrs[3])
    self.assertNotEqual(batch_ptrs[0], batch_ptrs[1])
    self.assertNotEqual(batch_ptrs[2], batch_ptrs[3])

if __name__ == "__main__":
  absltest.main()

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