lix/tests/unit/libutil/lru-cache.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

130 lines
4 KiB
C++

#include "lru-cache.hh"
#include <gtest/gtest.h>
namespace nix {
/* ----------------------------------------------------------------------------
* size
* --------------------------------------------------------------------------*/
TEST(LRUCache, sizeOfEmptyCacheIsZero) {
LRUCache<std::string, std::string> c(10);
ASSERT_EQ(c.size(), 0);
}
TEST(LRUCache, sizeOfSingleElementCacheIsOne) {
LRUCache<std::string, std::string> c(10);
c.upsert("foo", "bar");
ASSERT_EQ(c.size(), 1);
}
/* ----------------------------------------------------------------------------
* upsert / get
* --------------------------------------------------------------------------*/
TEST(LRUCache, getFromEmptyCache) {
LRUCache<std::string, std::string> c(10);
auto val = c.get("x");
ASSERT_EQ(val.has_value(), false);
}
TEST(LRUCache, getExistingValue) {
LRUCache<std::string, std::string> c(10);
c.upsert("foo", "bar");
auto val = c.get("foo");
ASSERT_EQ(val, "bar");
}
TEST(LRUCache, getNonExistingValueFromNonEmptyCache) {
LRUCache<std::string, std::string> c(10);
c.upsert("foo", "bar");
auto val = c.get("another");
ASSERT_EQ(val.has_value(), false);
}
TEST(LRUCache, upsertOnZeroCapacityCache) {
LRUCache<std::string, std::string> c(0);
c.upsert("foo", "bar");
auto val = c.get("foo");
ASSERT_EQ(val.has_value(), false);
}
TEST(LRUCache, updateExistingValue) {
LRUCache<std::string, std::string> c(1);
c.upsert("foo", "bar");
auto val = c.get("foo");
ASSERT_EQ(val.value_or("error"), "bar");
ASSERT_EQ(c.size(), 1);
c.upsert("foo", "changed");
val = c.get("foo");
ASSERT_EQ(val.value_or("error"), "changed");
ASSERT_EQ(c.size(), 1);
}
TEST(LRUCache, overwriteOldestWhenCapacityIsReached) {
LRUCache<std::string, std::string> c(3);
c.upsert("one", "eins");
c.upsert("two", "zwei");
c.upsert("three", "drei");
ASSERT_EQ(c.size(), 3);
ASSERT_EQ(c.get("one").value_or("error"), "eins");
// exceed capacity
c.upsert("another", "whatever");
ASSERT_EQ(c.size(), 3);
// Retrieving "one" makes it the most recent element thus
// two will be the oldest one and thus replaced.
ASSERT_EQ(c.get("two").has_value(), false);
ASSERT_EQ(c.get("another").value(), "whatever");
}
/* ----------------------------------------------------------------------------
* clear
* --------------------------------------------------------------------------*/
TEST(LRUCache, clearEmptyCache) {
LRUCache<std::string, std::string> c(10);
c.clear();
ASSERT_EQ(c.size(), 0);
}
TEST(LRUCache, clearNonEmptyCache) {
LRUCache<std::string, std::string> c(10);
c.upsert("one", "eins");
c.upsert("two", "zwei");
c.upsert("three", "drei");
ASSERT_EQ(c.size(), 3);
c.clear();
ASSERT_EQ(c.size(), 0);
}
/* ----------------------------------------------------------------------------
* erase
* --------------------------------------------------------------------------*/
TEST(LRUCache, eraseFromEmptyCache) {
LRUCache<std::string, std::string> c(10);
ASSERT_EQ(c.erase("foo"), false);
ASSERT_EQ(c.size(), 0);
}
TEST(LRUCache, eraseMissingFromNonEmptyCache) {
LRUCache<std::string, std::string> c(10);
c.upsert("one", "eins");
ASSERT_EQ(c.erase("foo"), false);
ASSERT_EQ(c.size(), 1);
ASSERT_EQ(c.get("one").value_or("error"), "eins");
}
TEST(LRUCache, eraseFromNonEmptyCache) {
LRUCache<std::string, std::string> c(10);
c.upsert("one", "eins");
ASSERT_EQ(c.erase("one"), true);
ASSERT_EQ(c.size(), 0);
ASSERT_EQ(c.get("one").value_or("empty"), "empty");
}
}