[M6] tests: levenshtein + pc_scan + brute_scan + findmodule_scan + last_failure_dir + cmd_linkdb_add + codegen PkgConfig/brute-force

tests/last_failure_dir.cpp

@@ -0,0 +1,59 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.resolver;
+import std;
+
+using cargoxx::resolver::last_failure_dir;
+
+namespace {
+
+struct EnvScope {
+    EnvScope(const char* k, std::optional<std::string> v) : key(k) {
+        if (auto* prior = std::getenv(key)) {
+            previous = std::string{prior};
+        }
+        if (v) {
+            setenv(key, v->c_str(), 1);
+        } else {
+            unsetenv(key);
+        }
+    }
+    ~EnvScope() {
+        if (previous) {
+            setenv(key, previous->c_str(), 1);
+        } else {
+            unsetenv(key);
+        }
+    }
+    const char* key;
+    std::optional<std::string> previous;
+};
+
+} // namespace
+
+TEST_CASE("last_failure_dir honors XDG_CACHE_HOME when set",
+          "[resolver][last_failure_dir]") {
+    EnvScope xdg{"XDG_CACHE_HOME", "/tmp/xdg-test"};
+
+    auto p = last_failure_dir("sqlite");
+    REQUIRE(p.string() == "/tmp/xdg-test/cargoxx/last-failure/sqlite");
+}
+
+TEST_CASE("last_failure_dir falls back to $HOME/.cache when XDG is unset",
+          "[resolver][last_failure_dir]") {
+    EnvScope xdg{"XDG_CACHE_HOME", std::nullopt};
+    EnvScope home{"HOME", "/tmp/home-test"};
+
+    auto p = last_failure_dir("fmt");
+    REQUIRE(p.string() == "/tmp/home-test/.cache/cargoxx/last-failure/fmt");
+}
+
+TEST_CASE("last_failure_dir uses cwd-based fallback when neither var is set",
+          "[resolver][last_failure_dir]") {
+    EnvScope xdg{"XDG_CACHE_HOME", std::nullopt};
+    EnvScope home{"HOME", std::nullopt};
+
+    auto p = last_failure_dir("obscure");
+    REQUIRE(p.filename() == "obscure");
+    REQUIRE(p.parent_path().filename() == ".cargoxx-last-failure");
+}