public void SetPythonPath()

{

PythonEngine.Initialize();

string path = PythonEngine.PythonPath;

const string moduleName = "pytest";

bool importShouldSucceed;

try

{

Py.Import(moduleName);

importShouldSucceed = true;

}

catch

{

importShouldSucceed = false;

}

string[] paths = Py.Import("sys").GetAttr("path").As<string[]>();

string path = string.Join(System.IO.Path.PathSeparator.ToString(), paths);

// path should not be set to PythonEngine.PythonPath here.

// PythonEngine.PythonPath gets the default module search path, not the full search path.

// The list sys.path is initialized with this value on interpreter startup;

// it can be (and usually is) modified later to change the search path for loading modules.

// See https://docs.python.org/3/c-api/init.html#c.Py_GetPath

// After PythonPath is set, then PythonEngine.PythonPath will correctly return the full search path.

PythonEngine.Shutdown();

PythonEngine.PythonPath = path;

PythonEngine.Initialize();

Assert.AreEqual(path, PythonEngine.PythonPath);

if (importShouldSucceed) Py.Import(moduleName);

PythonEngine.Shutdown();

}

}