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lix/tests/unit/libutil/pool.cc
John Ericson f7f37035c8 Move tests to separate directories, and document
Today, with the tests inside a `tests` intermingled with the
corresponding library's source code, we have a few problems:

- We have to be careful that wildcards don't end up with tests being
  built as part of Nix proper, or test headers being installed as part
  of Nix proper.

- Tests in libraries but not executables is not right:

  - It means each executable runs the previous unit tests again, because
    it needs the libraries.

  - It doesn't work right on Windows, which doesn't want you to load a
    DLL just for the side global variable . It could be made to work
    with the dlopen equivalent, but that's gross!

This reorg solves these problems.

There is a remaining problem which is that sibbling headers (like
`hash.hh` the test header vs `hash.hh` the main `libnixutil` header) end
up shadowing each other. This PR doesn't solve that. That is left as
future work for a future PR.

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>

(cherry picked from commit 91b6833686a6a6d9eac7f3f66393ec89ef1d3b57)
(cherry picked from commit a61e42adb528b3d40ce43e07c79368d779a8b624)
2023-12-01 13:05:03 -05:00

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);
}
}
}