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/*
* Copyright 2018 The Android Open Source Project
*
* 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.
*/
#include <thread>
#include <iostream>
#include <gtest/gtest.h>
#include "utils/LockFreeQueue.h"
/**
* Tests
* =====
*
* READ/POP:
* - if queue is empty return false
* - if queue has elements return true
* - returns correct value once
* - returns correct value more than once
*
* WRITE/PUSH:
* - if queue is full return false
* - if queue has space return true
*
* WRAP:
* - read from full queue, then write one more element, then correct read
*
* PEEK:
* - peek once
* - peek twice
*
* SIZE:
* - correct zero
* - correct once
* - correct many
*
* MULTI-THREADED:
* - write and read concurrently, queue is empty at end and item order is maintained
*
* CANNOT TEST:
* - read/writes correct after wraparound (takes too long to run)
* - Constructing queue with non power of 2 capacity results in assert failure (needs death test)
* - Constructing queue with signed type results in assert failure (needs death test)
*
*/
constexpr int kQueueCapacity = 2;
class TestLockFreeQueue : public ::testing::Test {
public:
int result1;
int result2;
int result3;
LockFreeQueue<int, kQueueCapacity> q;
};
TEST_F(TestLockFreeQueue, PopReturnsFalseWhenEmpty){
bool result = q.pop(result1);
ASSERT_EQ(result, false);
}
TEST_F(TestLockFreeQueue, PopReturnsTrueWhenNotEmpty){
q.push(123);
bool result = q.pop(result1);
ASSERT_EQ(result, true);
}
TEST_F(TestLockFreeQueue, PopReturnsOneCorrectValue){
q.push(123);
q.pop(result1);
ASSERT_EQ(result1, 123);
}
TEST_F(TestLockFreeQueue, PopReturnsManyCorrectValues){
q.push(123);
q.push(456);
q.pop(result1);
q.pop(result2);
ASSERT_EQ(result1, 123);
ASSERT_EQ(result2, 456);
}
TEST_F(TestLockFreeQueue, PushWhenFullReturnsFalse){
q.push(123);
q.push(123);
ASSERT_EQ(q.push(123), false);
}
TEST_F(TestLockFreeQueue, PushWhenSpaceAvailableReturnsTrue){
ASSERT_EQ(q.push(123), true);
}
TEST_F(TestLockFreeQueue, PushHandlesWrapCorrectly){
q.push(123);
q.push(234);
q.pop(result1);
q.push(999);
q.pop(result2);
ASSERT_EQ(result2, 234);
q.pop(result3);
ASSERT_EQ(result3, 999);
}
TEST_F(TestLockFreeQueue, PeekWhenEmptyReturnsFalse){
ASSERT_EQ(q.peek(result1), false);
}
TEST_F(TestLockFreeQueue, PeekWhenNotEmptyReturnsTrue){
q.push(123);
ASSERT_EQ(q.peek(result1), true);
}
TEST_F(TestLockFreeQueue, PeekReturnsCorrectValueOnce){
q.push(456);
q.peek(result1);
ASSERT_EQ(result1, 456);
}
TEST_F(TestLockFreeQueue, PeekReturnsCorrectValueTwice){
q.push(456);
q.peek(result1);
q.peek(result2);
ASSERT_EQ(result2, 456);
}
TEST_F(TestLockFreeQueue, SizeReturnsZeroAfterInit){
ASSERT_EQ(q.size(), 0);
}
TEST_F(TestLockFreeQueue, SizeIsOneAfterPushOnce){
q.push(321);
ASSERT_EQ(q.size(), 1);
}
TEST_F(TestLockFreeQueue, SizeIsCorrectAfterPushingMaxItems){
for (int i = 0; i < kQueueCapacity; ++i) { q.push(i); }
ASSERT_EQ(q.size(), kQueueCapacity);
}
TEST_F(TestLockFreeQueue, SizeCorrectAfterWriteCounterWraps){
const uint32_t kCapacity = (uint32_t) 1 << 7;
LockFreeQueue<int, kCapacity, uint8_t> myQ;
for (int i = 0; i < UINT8_MAX; ++i) {
myQ.push(i);
myQ.pop(result1);
}
myQ.push(1);
ASSERT_EQ(myQ.size(), 1);
}
TEST_F(TestLockFreeQueue, MultiThreadedTest){
// Push and pop from the queue concurrently
// Check that the queue is empty
// Check that the order of the read values matches the order of the written values
constexpr int kQueueCapacity = 2048;
LockFreeQueue<int, kQueueCapacity> myQ;
std::array<int, kQueueCapacity> sourceData;
std::array<int, kQueueCapacity> targetData { 0 };
// Populate the source data
for (int i = 0; i < kQueueCapacity; i++){
sourceData[i] = i;
}
std::thread writer([&myQ, &sourceData](){
for (int i = 0; i < kQueueCapacity; i++){
myQ.push(sourceData[i]);
}
});
std::thread reader([&myQ, &targetData](){
for (int i = 0; i < kQueueCapacity; i++){
// pop the latest element, or wait for it to become available
while (!myQ.pop(targetData[i])){
std::cout << "Waiting for element at index " << i << " to be written" << std::endl;
usleep(500);
}
}
});
writer.join();
reader.join();
int v;
ASSERT_FALSE(myQ.pop(v));
// Check that the target matches the source
for (int i = 0; i < kQueueCapacity; i++){
ASSERT_EQ(sourceData[i], targetData[i]) << "Elements at index " << i << " did not match";
}
}
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