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

tests/levenshtein.cpp

@@ -0,0 +1,36 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.util;
+import std;
+
+using cargoxx::util::levenshtein;
+
+TEST_CASE("levenshtein of equal strings is zero", "[util][levenshtein]") {
+    REQUIRE(levenshtein("", "") == 0);
+    REQUIRE(levenshtein("sqlite", "sqlite") == 0);
+}
+
+TEST_CASE("levenshtein counts a single suffix character", "[util][levenshtein]") {
+    REQUIRE(levenshtein("sqlite", "sqlite3") == 1);
+    REQUIRE(levenshtein("fmt", "fmtlib") == 3);
+}
+
+TEST_CASE("levenshtein is symmetric", "[util][levenshtein]") {
+    REQUIRE(levenshtein("sqlite", "sqlite3") == levenshtein("sqlite3", "sqlite"));
+    REQUIRE(levenshtein("abseil-cpp", "absl") == levenshtein("absl", "abseil-cpp"));
+}
+
+TEST_CASE("levenshtein counts a single substitution", "[util][levenshtein]") {
+    REQUIRE(levenshtein("kitten", "sitten") == 1);
+    REQUIRE(levenshtein("kitten", "kittes") == 1);
+}
+
+TEST_CASE("levenshtein matches the classic kitten/sitting example",
+          "[util][levenshtein]") {
+    REQUIRE(levenshtein("kitten", "sitting") == 3);
+}
+
+TEST_CASE("levenshtein handles empty inputs", "[util][levenshtein]") {
+    REQUIRE(levenshtein("", "abc") == 3);
+    REQUIRE(levenshtein("abc", "") == 3);
+}