@@ -181,13 +181,37 @@ public void SetProgramName()
181181public void SetPythonPath ( )
182182{
183183PythonEngine . Initialize ( ) ;
184- string path = PythonEngine . PythonPath ;
184+
185+ const string moduleName = "pytest" ;
186+ bool importShouldSucceed ;
187+ try
188+ {
189+ Py . Import ( moduleName ) ;
190+ importShouldSucceed = true ;
191+ }
192+ catch
193+ {
194+ importShouldSucceed = false ;
195+ }
196+
197+ string [ ] paths = Py . Import ( "sys" ) . GetAttr ( "path" ) . As < string [ ] > ( ) ;
198+ string path = string . Join ( System . IO . Path . PathSeparator . ToString ( ) , paths ) ;
199+
200+ // path should not be set to PythonEngine.PythonPath here.
201+ // PythonEngine.PythonPath gets the default module search path, not the full search path.
202+ // The list sys.path is initialized with this value on interpreter startup;
203+ // it can be (and usually is) modified later to change the search path for loading modules.
204+ // See https://docs.python.org/3/c-api/init.html#c.Py_GetPath
205+ // After PythonPath is set, then PythonEngine.PythonPath will correctly return the full search path.
206+
185207PythonEngine . Shutdown ( ) ;
186208
187209PythonEngine . PythonPath = path ;
188210PythonEngine . Initialize ( ) ;
189211
190212Assert . AreEqual ( path , PythonEngine . PythonPath ) ;
213+ if ( importShouldSucceed ) Py . Import ( moduleName ) ;
214+
191215PythonEngine . Shutdown ( ) ;
192216}
193217}