#!/usr/bin/python2
#
# Copyright 2015 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.

"""Unittests for server/cros/dynamic_suite/frontend_wrappers.py"""

import unittest

import common

from autotest_lib.server.cros.dynamic_suite import frontend_wrappers


class FrontendWrappersTest(unittest.TestCase):
    """Unit tests for frontend_wrappers global functions."""

    def testConvertTimeoutToRetryBasic(self):
        """Test converting timeout and delay values to retry attempts."""
        backoff = 2
        timeout_min = 10
        delay_sec = 10

        max_retry = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min, delay_sec)

        self.assertEquals(max_retry, 6)

    def testConvertTimeoutToRetryLimit(self):
        """Test approaching a change in attempt amount."""
        backoff = 2
        delay_sec = 10
        timeout_min_lower_limit = 42.499999
        timeout_min_at_limit = 42.5
        timeout_min_upper_limit = 42.599999

        max_retry_lower_limit = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min_lower_limit, delay_sec)

        max_retry_at_limit = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min_at_limit, delay_sec)

        max_retry_upper_limit = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min_upper_limit, delay_sec)

        # Eight attempts with a backoff factor of two should be sufficient
        # for timeouts up to 2550 seconds (or 42.5 minutes).
        self.assertEquals(max_retry_lower_limit, 8)
        self.assertEquals(max_retry_at_limit, 8)

        # We expect to see nine attempts, as we are above the 42.5 minute
        # threshold.
        self.assertEquals(max_retry_upper_limit, 9)

    def testConvertTimeoutToRetrySmallTimeout(self):
        """Test converting to retry attempts when a small timeout is used."""
        backoff = 2
        timeout_min = 0.01
        delay_sec = 10

        max_retry = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min, delay_sec)

        # The number of attempts should be less than one using the formula
        # outlined in the function, but, we always round up to the nearest
        # integer.
        self.assertEquals(max_retry, 1)

    def testConvertTimeoutToRetrySmallDelay(self):
        """Test converting to retry attempts when the delay is small."""
        backoff = 2
        timeout_min = 30
        delay_sec = 0.01

        max_retry = frontend_wrappers.convert_timeout_to_retry(
                backoff, timeout_min, delay_sec)

        # The number of retries shouldn't be too large despite the small
        # delay as a result of backing off in an exponential fashion.
        self.assertEquals(max_retry, 18)


if __name__ == '__main__':
    unittest.main()