lix/src/libutil/tests/pool.cc
2020-06-10 22:29:50 +02:00

128 lines
4.3 KiB
C++

#include "pool.hh"
#include <gtest/gtest.h>
namespace nix {
struct TestResource
{
TestResource() {
static int counter = 0;
num = counter++;
}
int dummyValue = 1;
bool good = true;
int num;
};
/* ----------------------------------------------------------------------------
* Pool
* --------------------------------------------------------------------------*/
TEST(Pool, freshPoolHasZeroCountAndSpecifiedCapacity) {
auto isGood = [](const ref<TestResource> & r) { return r->good; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
ASSERT_EQ(pool.count(), 0);
ASSERT_EQ(pool.capacity(), 1);
}
TEST(Pool, freshPoolCanGetAResource) {
auto isGood = [](const ref<TestResource> & r) { return r->good; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
ASSERT_EQ(pool.count(), 0);
TestResource r = *(pool.get());
ASSERT_EQ(pool.count(), 1);
ASSERT_EQ(pool.capacity(), 1);
ASSERT_EQ(r.dummyValue, 1);
ASSERT_EQ(r.good, true);
}
TEST(Pool, capacityCanBeIncremented) {
auto isGood = [](const ref<TestResource> & r) { return r->good; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
ASSERT_EQ(pool.capacity(), 1);
pool.incCapacity();
ASSERT_EQ(pool.capacity(), 2);
}
TEST(Pool, capacityCanBeDecremented) {
auto isGood = [](const ref<TestResource> & r) { return r->good; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
ASSERT_EQ(pool.capacity(), 1);
pool.decCapacity();
ASSERT_EQ(pool.capacity(), 0);
}
TEST(Pool, flushBadDropsOutOfScopeResources) {
auto isGood = [](const ref<TestResource> & r) { return false; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
{
auto _r = pool.get();
ASSERT_EQ(pool.count(), 1);
}
pool.flushBad();
ASSERT_EQ(pool.count(), 0);
}
// Test that the resources we allocate are being reused when they are still good.
TEST(Pool, reuseResource) {
auto isGood = [](const ref<TestResource> & r) { return true; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
// Compare the instance counter between the two handles. We expect them to be equal
// as the pool should hand out the same (still) good one again.
int counter = -1;
{
Pool<TestResource>::Handle h = pool.get();
counter = h->num;
} // the first handle goes out of scope
{ // the second handle should contain the same resource (with the same counter value)
Pool<TestResource>::Handle h = pool.get();
ASSERT_EQ(h->num, counter);
}
}
// Test that the resources we allocate are being thrown away when they are no longer good.
TEST(Pool, badResourceIsNotReused) {
auto isGood = [](const ref<TestResource> & r) { return false; };
auto createResource = []() { return make_ref<TestResource>(); };
Pool<TestResource> pool = Pool<TestResource>((size_t)1, createResource, isGood);
// Compare the instance counter between the two handles. We expect them
// to *not* be equal as the pool should hand out a new instance after
// the first one was returned.
int counter = -1;
{
Pool<TestResource>::Handle h = pool.get();
counter = h->num;
} // the first handle goes out of scope
{
// the second handle should contain a different resource (with a
//different counter value)
Pool<TestResource>::Handle h = pool.get();
ASSERT_NE(h->num, counter);
}
}
}