Add tests for GPU parsing, concurrency limits, network config, health

GPU: valid types, invalid type, case-insensitive. Concurrency:
429 on limit, counter decrements on error. Network: CIDR
parsing, empty CIDR. Health: endpoint returns ok.

Author: manascb1344

tests/test_app.py

@@ -425,3 +425,116 @@ def test_sanitize_error_message_empty():
 
     assert _sanitize_error_message("") == "[empty response]"
     assert _sanitize_error_message(None) == "[empty response]"
+
+
+# =============================================================================
+# GPU / network / concurrency / health tests
+# =============================================================================
+
+
+def test_get_gpu_config_valid_types():
+    from app import _get_gpu_config
+
+    for gpu_key in ["t4", "l4", "a100", "a100-80gb", "h100"]:
+        with patch("app.modal") as mock_modal:
+            mock_modal.gpu.T4.return_value = "mock_gpu"
+            mock_modal.gpu.L4.return_value = "mock_gpu"
+            mock_modal.gpu.A100.return_value = "mock_gpu"
+            mock_modal.gpu.A100_80GB.return_value = "mock_gpu"
+            mock_modal.gpu.H100.return_value = "mock_gpu"
+            result = _get_gpu_config(gpu_key)
+            assert result is not None
+
+
+def test_get_gpu_config_invalid_type():
+    from app import _get_gpu_config
+
+    with patch("app.modal"):
+        result = _get_gpu_config("nonexistent-gpu")
+        assert result is None
+
+
+def test_get_gpu_config_case_insensitive():
+    from app import _get_gpu_config
+
+    with patch("app.modal") as mock_modal:
+        mock_modal.gpu.T4.return_value = "mock_gpu"
+        with patch.dict("app.GPU_LABEL_TO_ATTR", {"T4": "T4"}, clear=False):
+            result = _get_gpu_config("T4")
+            assert result is not None
+
+
+@pytest.mark.asyncio
+async def test_concurrency_limit_returns_429():
+    from fastapi import HTTPException
+
+    import app as app_module
+    from app import github_webhook
+
+    original = app_module.MAX_CONCURRENT_PER_REPO
+    app_module.MAX_CONCURRENT_PER_REPO = 1
+    app_module._concurrent_jobs["owner/repo"] = 1
+
+    body = _make_webhook_body()
+    request = _make_request(body)
+
+    try:
+        with pytest.raises(HTTPException) as exc_info:
+            await github_webhook(request)
+        assert exc_info.value.status_code == 429
+    finally:
+        app_module.MAX_CONCURRENT_PER_REPO = original
+        app_module._concurrent_jobs.clear()
+
+
+@pytest.mark.asyncio
+async def test_concurrency_counter_decrements():
+    import httpx
+
+    import app as app_module
+    from app import github_webhook
+
+    original = app_module.MAX_CONCURRENT_PER_REPO
+    app_module.MAX_CONCURRENT_PER_REPO = 5
+    app_module._concurrent_jobs.clear()
+
+    body = _make_webhook_body()
+    request = _make_request(body)
+
+    req = httpx.Request("POST", "http://test")
+    mock_response = httpx.Response(200, json={"encoded_jit_config": "jit-config"}, request=req)
+
+    try:
+        with patch("app._call_github_api", new=AsyncMock(return_value=mock_response)):
+            with patch("app.modal.Sandbox.create", side_effect=Exception("sandbox failure")):
+                with pytest.raises(Exception):
+                    await github_webhook(request)
+    finally:
+        assert app_module._concurrent_jobs.get("owner/repo", 0) == 0
+        app_module.MAX_CONCURRENT_PER_REPO = original
+
+
+def test_network_config_defaults():
+    import app
+
+    assert app.BLOCK_NETWORK is False or app.BLOCK_NETWORK is True
+
+
+def test_allowed_cidrs_parsing():
+    cidrs_str = "10.0.0.0/8, 172.16.0.0/12"
+    cidrs = [c.strip() for c in cidrs_str.split(",") if c.strip()] if cidrs_str else None
+    assert cidrs == ["10.0.0.0/8", "172.16.0.0/12"]
+
+
+def test_allowed_cidrs_empty():
+    cidrs_str = ""
+    cidrs = [c.strip() for c in cidrs_str.split(",") if c.strip()] if cidrs_str else None
+    assert cidrs is None
+
+
+@pytest.mark.asyncio
+async def test_health_endpoint():
+    from app import health
+
+    result = await health(MagicMock())
+    assert result == {"status": "ok"}