[KNITRO] Add license validation (metab0t#80)

* Add license validation for KNITRO library and update related tests

* fix merge conflicts

---------

Co-authored-by: Yue Yang <metab0t@users.noreply.github.com>

Author: eminyouskn

include/pyoptinterface/knitro_model.hpp

@@ -93,6 +93,8 @@ APILIST
 bool is_library_loaded();
 
 bool load_library(const std::string &path);
+
+bool has_valid_license();
 } // namespace knitro
 
 struct KNITROFreeProblemT

lib/knitro_model.cpp

@@ -48,6 +48,26 @@ bool load_library(const std::string &path)
 		return false;
 	}
 }
+
+bool has_valid_license()
+{
+	if (!is_library_loaded())
+	{
+		throw std::runtime_error("KNITRO library not loaded");
+	}
+
+	LM_context *lm = nullptr;
+	int error = KN_checkout_license(&lm);
+	if (error == 0)
+	{
+		KN_release_license(&lm);
+		return true;
+	}
+	else
+	{
+		return false;
+	}
+}
 } // namespace knitro
 
 void ensure_library_loaded()

lib/knitro_model_ext.cpp

@@ -15,6 +15,7 @@ NB_MODULE(knitro_model_ext, m)
 
 	m.def("is_library_loaded", &knitro::is_library_loaded);
 	m.def("load_library", &knitro::load_library);
+	m.def("has_valid_license", &knitro::has_valid_license);
 
 	bind_knitro_constants(m);
 

src/pyoptinterface/knitro.py

@@ -3,6 +3,7 @@
     KN,
     load_library,
     is_library_loaded,
+    has_valid_license,
 )
 
 __all__ = [
@@ -12,4 +13,5 @@
     "autoload_library",
     "load_library",
     "is_library_loaded",
+    "has_valid_license",
 ]

tests/conftest.py

@@ -23,7 +23,7 @@ def c():
 if copt.is_library_loaded():
     nlp_model_dict["copt"] = copt.Model
 
-if knitro.is_library_loaded():
+if knitro.is_library_loaded() and knitro.has_valid_license():
     nlp_model_dict["knitro"] = knitro.Model
 
 
@@ -46,7 +46,7 @@ def nlp_model_ctor(request):
     model_interface_dict_full["mosek"] = mosek.Model
 if highs.is_library_loaded():
     model_interface_dict_full["highs"] = highs.Model
-if knitro.is_library_loaded():
+if knitro.is_library_loaded() and knitro.has_valid_license():
     model_interface_dict_full["knitro"] = knitro.Model
 
 

tests/test_knitro.py

@@ -5,7 +5,8 @@
 import pyoptinterface as poi
 
 pytestmark = pytest.mark.skipif(
-    not knitro.is_library_loaded(), reason="KNITRO library is not loaded"
+    not knitro.is_library_loaded() or not knitro.has_valid_license(),
+    reason="KNITRO library is not loaded or license is not valid",
 )