utils/timer_unittest.py

# Copyright 2021 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Tests for timer."""

import re
import time

import pytest

from chromite.utils import timer


DELTA = 1.0


@pytest.fixture(autouse=True)
def time_mock_fixture(monkeypatch):
  last_t = 0.0

  def time_mock():
    nonlocal last_t
    last_t += DELTA
    return last_t

  monkeypatch.setattr(time, 'perf_counter', time_mock)


def test_timer_delta(caplog):
  """Test basic usage of a Timer."""
  with timer.timer() as t:
    pass
  assert re.search(f'{DELTA}[0-9]*s', caplog.text) is not None
  assert t.delta == DELTA


def test_timer_average():
  """Test the timer __add__ and __truediv__ functions."""
  timers = []
  range_len = 10
  for x in range(range_len):
    with timer.Timer(str(x)) as t:
      pass
    timers.append(t)

  assert sum(timers, start=timer.Timer()).delta == DELTA * range_len
  assert (sum(timers, start=timer.Timer()) / len(timers)).delta == DELTA


def test_timer_decorator():
  """Test the timed decorator."""
  name = 'name'
  output_fn_called = False

  # Output function to check the value.
  def output_fn(value):
    nonlocal output_fn_called
    output_fn_called = True
    assert re.match(f'{name}: {DELTA}[0-9]*s', value) is not None

  # The decorated function.
  @timer.timed(name, output_fn)
  def timed_fn():
    pass

  # Run the function to trigger the test.
  timed_fn()

  assert output_fn_called