more tests

tests/Cuda/Cuda.cpp

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+/*
+Crafter® Build
+Copyright (C) 2026 Catcrafts®
+Catcrafts.net
+
+LGPL-3.0-only.
+
+End-to-end CUDA build through the V2 pipeline:
+the inner project.cpp registers a .cu translation unit via cfg.cuda, and
+crafter.build-lib drives nvcc to produce a host object that links into
+the final executable. The test skips when the CUDA SDK is missing
+(CI hosts have neither nvcc nor libcudart) and otherwise runs the built
+binary to confirm the .cu's host-callable entry returns through the link.
+
+No GPU is required: the kernel is staged but never launched, so cudart's
+fat-binary registration runs at startup but device init does not.
+*/
+
+import std;
+import Crafter.Build;
+#include "../_shared/TestUtil.h"
+namespace fs = std::filesystem;
+using namespace TestUtil;
+using namespace Crafter;
+
+namespace {
+    bool ToolPresent(std::string_view name) {
+        return std::system(std::format("which {} > /dev/null 2>&1", name).c_str()) == 0;
+    }
+}
+
+int main() {
+    try {
+        if (!ToolPresent("nvcc")) {
+            Skip("nvcc not on PATH — install the CUDA SDK to enable this test");
+        }
+
+        // Resolve the CUDA root from nvcc's own location so the inner project
+        // can point the linker at libcudart.so without a hardcoded path.
+        // Standard SDK layout puts nvcc at <root>/bin/nvcc and cudart at
+        // <root>/lib64; if either assumption is broken we skip rather than
+        // fail, since that means the install is non-standard.
+        fs::path cwd = fs::current_path();
+        auto probe = RunInDir(cwd, "command -v nvcc");
+        if (probe.exitCode != 0 || probe.output.empty()) {
+            Skip("nvcc not on PATH");
+        }
+        std::string nvccPath = probe.output;
+        while (!nvccPath.empty() && (nvccPath.back() == '\n' || nvccPath.back() == '\r')) {
+            nvccPath.pop_back();
+        }
+        fs::path real = fs::canonical(nvccPath);
+        fs::path cudaLibDir = real.parent_path().parent_path() / "lib64";
+        if (!fs::exists(cudaLibDir / "libcudart.so")) {
+            Skip(std::format("libcudart.so not found at {} — incomplete CUDA SDK install",
+                cudaLibDir.string()));
+        }
+        ::setenv("CRAFTER_CUDA_LIBDIR", cudaLibDir.string().c_str(), 1);
+
+        fs::path src = cwd / "tests" / "Cuda" / "inner";
+        Configuration cfg = LoadFixture("Cuda", src);
+        fs::path work = fs::current_path();
+
+        auto br = BuildOnce(cfg);
+        if (!br.result.empty()) {
+            std::println(std::cerr, "build failed:\n{}", br.result);
+            return 1;
+        }
+
+        fs::path artifact = work / "bin" / "cuda-test-x86_64-pc-linux-gnu-native" / "cuda-test";
+        if (!fs::exists(artifact)) {
+            std::println(std::cerr, "expected artifact missing at {}", artifact.string());
+            return 1;
+        }
+
+        // libcudart.so is on the system loader path on most CUDA installs
+        // (Arch puts /opt/cuda/lib64 in /etc/ld.so.conf.d), but other distros
+        // don't, so set LD_LIBRARY_PATH explicitly for the run.
+        auto run = RunInDir(work, std::format(
+            "LD_LIBRARY_PATH='{}' '{}'", cudaLibDir.string(), artifact.string()));
+        if (run.exitCode != 0) {
+            std::println(std::cerr, "artifact exited nonzero (rc={}):\n{}", run.exitCode, run.output);
+            return 1;
+        }
+        if (run.output != "answer=42\n") {
+            std::println(std::cerr, "output mismatch:\n  expected: \"answer=42\\n\"\n  got: {:?}", run.output);
+            return 1;
+        }
+        return 0;
+    } catch (const std::exception& e) {
+        std::println(std::cerr, "test exception: {}", e.what());
+        return 1;
+    }
+}