Fix Windows memory budget detection

tests/test_node_startup.py

@@ -13,6 +13,7 @@ from meshnet_node.downloader import download_shard, write_shard_archive
 from meshnet_node.hardware import detect_hardware, benchmark_throughput
 from meshnet_node.startup import (
     _infer_relay_url_from_tracker,
+    _memory_budget,
     _probationary_status_line,
     run_startup,
 )
@@ -34,13 +35,80 @@ def test_detect_hardware_returns_valid_profile():
     assert isinstance(hw.get("ram_mb"), int)
     assert hw["ram_mb"] > 0
     if hw["device"] == "cpu":
-        assert hw["gpu_name"] is None
-        assert hw["vram_mb"] == 0
+        assert hw["gpu_name"] is None or isinstance(hw["gpu_name"], str)
+        assert hw["vram_mb"] >= 0
     else:
         assert isinstance(hw["gpu_name"], str) and hw["gpu_name"]
         assert hw["vram_mb"] > 0
 
 
+def test_windows_ram_fallback_is_used_when_sysconf_is_unavailable(monkeypatch):
+    """Windows hosts do not have os.sysconf; RAM must not collapse to 0 MB."""
+    import meshnet_node.hardware as hardware_mod
+
+    monkeypatch.setattr(
+        hardware_mod.os,
+        "sysconf",
+        lambda _name: (_ for _ in ()).throw(AttributeError()),
+        raising=False,
+    )
+    monkeypatch.setattr(hardware_mod, "_detect_windows_ram_mb", lambda: 64 * 1024)
+
+    assert hardware_mod._detect_ram_mb() == 64 * 1024
+
+
+def test_windows_gpu_memory_fallback_preserves_cpu_execution(monkeypatch):
+    """A Windows-visible GPU is reported, but CUDA execution is not claimed without CUDA."""
+    import meshnet_node.hardware as hardware_mod
+
+    calls = []
+
+    class FakeResult:
+        def __init__(self, stdout):
+            self.returncode = 0
+            self.stdout = stdout
+
+    def fake_run(command, *args, **kwargs):
+        calls.append(command)
+        joined = " ".join(command)
+        if "nvidia-smi" in joined:
+            raise FileNotFoundError
+        if "Win32_ComputerSystem" in joined:
+            return FakeResult(str(80 * 1024 * 1024 * 1024))
+        if "Win32_VideoController" in joined:
+            return FakeResult('{"Name":"NVIDIA GeForce RTX Laptop GPU","AdapterRAM":8589934592}')
+        raise AssertionError(command)
+
+    monkeypatch.setattr(
+        hardware_mod.os,
+        "sysconf",
+        lambda _name: (_ for _ in ()).throw(AttributeError()),
+        raising=False,
+    )
+    monkeypatch.setattr(hardware_mod.subprocess, "run", fake_run)
+    monkeypatch.setattr(hardware_mod, "_detect_windows_ram_mb", lambda: 80 * 1024)
+    monkeypatch.setitem(sys.modules, "torch", types.SimpleNamespace(cuda=types.SimpleNamespace(is_available=lambda: False)))
+
+    hw = hardware_mod.detect_hardware()
+
+    assert hw["device"] == "cpu"
+    assert hw["gpu_name"] == "NVIDIA GeForce RTX Laptop GPU"
+    assert hw["vram_mb"] == 8192
+    assert hw["shared_vram_mb"] == 40 * 1024
+    assert hw["ram_mb"] == 80 * 1024
+
+
+def test_memory_budget_uses_ram_for_cpu_and_shared_memory_for_cuda():
+    assert _memory_budget("cpu", vram_mb=8192, ram_mb=80 * 1024, shared_vram_mb=40 * 1024) == (
+        80 * 1024,
+        "RAM",
+    )
+    assert _memory_budget("cuda", vram_mb=8192, ram_mb=80 * 1024, shared_vram_mb=40 * 1024) == (
+        48 * 1024,
+        "VRAM + shared RAM",
+    )
+
+
 def test_benchmark_throughput_cpu_returns_positive():
     """CPU benchmark returns a positive float greater than the 1.0 error fallback."""
     result = benchmark_throughput("cpu")