Crafter.Build/tests/_shared/TestUtil.h

#pragma once
#include <stdlib.h>  // setenv (POSIX, not in `import std`)

namespace TestUtil {
    // Exit code 77 follows the autoconf convention. crafter-build's test
    // runner maps it to TestOutcome::Skipped and renders the test's stdout
    // as the reason. Use this when the test discovers at runtime that its
    // preconditions aren't met (tool missing, env unset, etc).
    [[noreturn]] inline void Skip(std::string_view reason) {
        std::print("{}", reason);
        std::exit(77);
    }

    inline std::string ReadFile(const std::filesystem::path& p) {
        std::ifstream f(p);
        std::stringstream ss;
        ss << f.rdbuf();
        return ss.str();
    }

    inline std::filesystem::path CopyFixtureToTemp(std::string_view testName, const std::filesystem::path& source) {
        namespace fs = std::filesystem;
        fs::path tmp = fs::temp_directory_path() / std::format("crafter-test-{}", testName);
        fs::remove_all(tmp);
        fs::copy(source, tmp, fs::copy_options::recursive);
        return tmp;
    }

    struct CmdResult {
        int exitCode;
        std::string output;
    };

    inline CmdResult RunInDir(const std::filesystem::path& cwd, std::string_view command) {
        namespace fs = std::filesystem;
        // Log inside cwd so parallel test drivers don't trample each other.
        fs::path log = cwd / ".crafter-cmd-output.log";
        std::string cmd = std::format("cd '{}' && {} > '{}' 2>&1",
            cwd.string(), command, log.string());
        int rc = std::system(cmd.c_str());
        std::string out = ReadFile(log);
        std::error_code ec;
        fs::remove(log, ec);
        return {rc, std::move(out)};
    }

    // Build cfg with a fresh dep cache. Convenient for outer-driver tests that
    // exercise the build API in-process and don't need to share the dep cache
    // across multiple Build() calls.
    inline Crafter::BuildResult BuildOnce(Crafter::Configuration& cfg) {
        std::unordered_map<std::filesystem::path, std::shared_future<Crafter::BuildResult>> depResults;
        std::mutex depMutex;
        return Crafter::Build(cfg, depResults, depMutex);
    }

    // Copy a fixture into a fresh temp dir, chdir there (so cfg.path = "./"
    // inside the inner project.cpp resolves to the temp dir), and load its
    // project.cpp. Common prep for in-process build/test API tests.
    //
    // Also sets CRAFTER_BUILD_HOME to <projectRoot>/share/crafter-build before
    // loading. The lib's default sourceDir is derived from /proc/self/exe, but
    // test exes live in tests/<Name>/bin/... rather than next to the project's
    // share/, so the default lookup misses. The test runner launches tests
    // with cwd = project root, so we capture that here before the chdir below.
    inline Crafter::Configuration LoadFixture(std::string_view testName,
                                              const std::filesystem::path& source,
                                              std::span<const std::string_view> args = {}) {
        auto projectRoot = std::filesystem::current_path();
        auto sharePath = projectRoot / "share" / "crafter-build";
        ::setenv("CRAFTER_BUILD_HOME", sharePath.string().c_str(), 1);

        auto work = CopyFixtureToTemp(testName, source);
        std::filesystem::current_path(work);
        return Crafter::LoadProject("project.cpp", args);
    }
}