diff --git a/Utilities/PythonInterpreter/vtkPythonInterpreter.cxx b/Utilities/PythonInterpreter/vtkPythonInterpreter.cxx
index 0471594..bc92c85 100644
--- a/Utilities/PythonInterpreter/vtkPythonInterpreter.cxx
+++ b/Utilities/PythonInterpreter/vtkPythonInterpreter.cxx
@@ -114,7 +114,9 @@ wchar_t* vtk_Py_UTF8ToWide(const char* arg)
 
   return result;
 }
+#endif
 
+#if PY_VERSION_HEX < 0x03080000
 std::string vtk_Py_WideToUTF8(const wchar_t* arg)
 {
   std::string result;
@@ -859,15 +861,20 @@ void vtkPythonInterpreter::SetupVTKPythonPaths()
   if (vtklib.empty())
   {
     VTKPY_DEBUG_MESSAGE(
-      "`GetVTKVersion` library couldn't be found. Will use `Py_GetProgramName` next.");
+      "`GetVTKVersion` library couldn't be found. Will use `sys.executable` next.");
   }
 
   if (vtklib.empty())
   {
-#if PY_VERSION_HEX >= 0x03000000
-    vtklib = vtk_Py_WideToUTF8(Py_GetProgramName());
+#if PY_VERSION_HEX >= 0x03080000
+    vtkPythonScopeGilEnsurer gilEnsurer;
+    PyObject* executable_path = PySys_GetObject("executable");
+    if (executable_path != Py_None)
+    {
+      vtklib = PyUnicode_AsUTF8AndSize(executable_path, nullptr);
+    }
 #else
-    vtklib = Py_GetProgramName();
+    vtklib = vtk_Py_WideToUTF8(Py_GetProgramName());
 #endif
   }
 
diff --git a/Wrapping/Python/vtkmodules/test/Testing.py b/Wrapping/Python/vtkmodules/test/Testing.py
index 59186bb..d0643c1 100644
--- a/Wrapping/Python/vtkmodules/test/Testing.py
+++ b/Wrapping/Python/vtkmodules/test/Testing.py
@@ -513,8 +513,10 @@ def test(cases):
     """
     # Make the test suites from the arguments.
     suites = []
-    for case in cases:
-        suites.append(unittest.makeSuite(case[0], case[1]))
+    loader = unittest.TestLoader()
+    # the "name" is ignored (it was always just 'test')
+    for test,name in cases:
+        suites.append(loader.loadTestsFromTestCase(test))
     test_suite = unittest.TestSuite(suites)
 
     # Now run the tests.
diff --git a/Wrapping/PythonCore/PyVTKNamespace.cxx b/Wrapping/PythonCore/PyVTKNamespace.cxx
index 927eef1..7460eb7 100644
--- a/Wrapping/PythonCore/PyVTKNamespace.cxx
+++ b/Wrapping/PythonCore/PyVTKNamespace.cxx
@@ -113,8 +113,10 @@ PyObject* PyVTKNamespace_New(const char* name)
   {
     // make sure python has readied the type object
     PyType_Ready(&PyVTKNamespace_Type);
-    // call the allocator provided by python for this type
-    self = PyVTKNamespace_Type.tp_alloc(&PyVTKNamespace_Type, 0);
+    // call the superclass new function
+    PyObject* empty = PyTuple_New(0);
+    self = PyVTKNamespace_Type.tp_base->tp_new(&PyVTKNamespace_Type, empty, nullptr);
+    Py_DECREF(empty);
     // call the superclass init function
     PyObject* args = PyTuple_New(1);
     PyTuple_SET_ITEM(args, 0, PyString_FromString(name));
diff --git a/Wrapping/PythonCore/PyVTKTemplate.cxx b/Wrapping/PythonCore/PyVTKTemplate.cxx
index e0ff31e..c89900f 100644
--- a/Wrapping/PythonCore/PyVTKTemplate.cxx
+++ b/Wrapping/PythonCore/PyVTKTemplate.cxx
@@ -788,8 +788,10 @@ PyObject* PyVTKTemplate_New(const char* name, const char* docstring)
 {
   // make sure python has readied the type object
   PyType_Ready(&PyVTKTemplate_Type);
-  // call the allocator provided by python for this type
-  PyObject* self = PyVTKTemplate_Type.tp_alloc(&PyVTKTemplate_Type, 0);
+  // call the superclass new function
+  PyObject* empty = PyTuple_New(0);
+  PyObject* self = PyVTKTemplate_Type.tp_base->tp_new(&PyVTKTemplate_Type, empty, nullptr);
+  Py_DECREF(empty);
   // call the superclass init function
   PyObject* args = PyTuple_New(2);
   PyTuple_SET_ITEM(args, 0, PyString_FromString(name));