[M5+] add resolver::vcpkg_probe

tests/vcpkg_probe_parse.cpp

@@ -0,0 +1,71 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.resolver;
+import cargoxx.util;
+import std;
+
+using cargoxx::resolver::parse_vcpkg_usage;
+using cargoxx::util::ErrorCode;
+
+TEST_CASE("parse_vcpkg_usage extracts find_package and a target",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(fmt provides CMake targets:
+
+    find_package(fmt CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE fmt::fmt)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "fmt CONFIG REQUIRED");
+    REQUIRE(r->targets == std::vector<std::string>{"fmt::fmt"});
+}
+
+TEST_CASE("parse_vcpkg_usage adds REQUIRED when missing", "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(spdlog CONFIG)
+    target_link_libraries(main PRIVATE spdlog::spdlog)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "spdlog CONFIG REQUIRED");
+}
+
+TEST_CASE("parse_vcpkg_usage dedupes targets", "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(boost CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE Boost::filesystem Boost::system Boost::filesystem)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->targets == std::vector<std::string>{"Boost::filesystem", "Boost::system"});
+}
+
+TEST_CASE("parse_vcpkg_usage skips generator-expression and bare-name tokens",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(qt6 CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE Qt6::Core $<TARGET_NAME:Qt6::Gui> mylib)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    // mylib lacks "::", $<...> contains '$' — both excluded.
+    REQUIRE(r->targets == std::vector<std::string>{"Qt6::Core"});
+}
+
+TEST_CASE("parse_vcpkg_usage errors when no find_package directive present",
+          "[resolver][vcpkg]") {
+    auto r = parse_vcpkg_usage("nothing useful here");
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::ResolutionUnknownPackage);
+}
+
+TEST_CASE("parse_vcpkg_usage handles target_link_libraries with PUBLIC visibility",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(eigen3 CONFIG REQUIRED)
+    target_link_libraries(main PUBLIC Eigen3::Eigen)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->targets == std::vector<std::string>{"Eigen3::Eigen"});
+}