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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "util/integer_division.h"
#include <chrono>
#include "gtest/gtest.h"
namespace openscreen {
namespace {
constexpr int kDenominators[2] = {3, 4};
// Common test routine that tests one of the integer division functions using a
// fixed denominator and stepping, one-by-one, over a range of numerators around
// zero.
template <typename Input, typename Output>
void TestRangeAboutZero(int denom,
int range_of_numerators,
int first_expected_result,
Output (*function_to_test)(Input, Input)) {
int expected_result = first_expected_result;
int count_until_next_change = denom;
for (int num = -range_of_numerators; num <= range_of_numerators; ++num) {
EXPECT_EQ(expected_result, function_to_test(Input(num), Input(denom)))
<< "num=" << num << ", denom=" << denom;
EXPECT_EQ(expected_result, function_to_test(Input(-num), Input(-denom)))
<< "num=" << (-num) << ", denom=" << (-denom);
--count_until_next_change;
if (count_until_next_change == 0) { // Next result will be one higher.
++expected_result;
count_until_next_change = denom;
}
}
}
TEST(IntegerDivision, DividesAndRoundsUpInts) {
auto* const function_to_test = &DivideRoundingUp<int>;
for (int denom : kDenominators) {
TestRangeAboutZero(denom, denom == 3 ? 11 : 15, -3, function_to_test);
}
}
TEST(IntegerDivision, DividesAndRoundsUpChronoDurations) {
auto* const function_to_test = &DivideRoundingUp<std::chrono::milliseconds>;
for (int denom : kDenominators) {
TestRangeAboutZero(denom, denom == 3 ? 11 : 15, -3, function_to_test);
}
}
// Assumption: DivideRoundingUp() is working (tested by the above two tests).
TEST(IntegerDivision, DividesPositivesAndRoundsUp) {
for (int num = 0; num <= 6; ++num) {
for (int denom = 1; denom <= 6; ++denom) {
EXPECT_EQ(DivideRoundingUp(num, denom),
DividePositivesRoundingUp(num, denom));
}
}
}
TEST(IntegerDivision, DividesAndRoundsNearestInts) {
auto* const function_to_test = &DivideRoundingNearest<int>;
for (int denom : kDenominators) {
TestRangeAboutZero(denom, denom == 3 ? 10 : 14, -3, function_to_test);
}
}
TEST(IntegerDivision, DividesAndRoundsNearestChronoDurations) {
auto* const function_to_test =
&DivideRoundingNearest<std::chrono::milliseconds>;
for (int denom : kDenominators) {
TestRangeAboutZero(denom, denom == 3 ? 10 : 14, -3, function_to_test);
}
}
// Assumption: DivideRoundingNearest() is working (tested by the above two
// tests).
TEST(IntegerDivision, DividesPositivesAndRoundsNearest) {
for (int num = 0; num <= 6; ++num) {
for (int denom = 1; denom <= 6; ++denom) {
EXPECT_EQ(DivideRoundingNearest(num, denom),
DividePositivesRoundingNearest(num, denom));
}
}
}
} // namespace
} // namespace openscreen
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