FEM: solver frame work, beside dir fix

src/Mod/Fem/femsolver/run.py

@@ -180,10 +180,13 @@ def getMachine(solver, path=None):
     :param path:
         A valid filesystem path which shall be associetad with the machine.
     """
+    # print(path)
     _DocObserver.attach()
     m = _machines.get(solver)
     if m is None or not _isPathValid(m, path):
         m = _createMachine(solver, path, testmode=False)
+        # print(m.__dir__())  # document these attributes somewhere
+        # print(m.directory)
     return m
 
 
@@ -244,7 +247,11 @@ def _getBesideDir(solver):
 
 def _getBesideBase(solver):
     path = os.path.splitext(solver.Document.FileName)[0]
-    if path is None:
+    # doc=App.newDocument()
+    # doc.FileName
+    # the above returns an empty string in FreeCAD 0.19
+    # https://forum.freecadweb.org/viewtopic.php?f=10&t=48842
+    if path is "":
         error_message = (
             "Please save the file before executing the solver. "
             "This must be done because the location of the working "
@@ -258,6 +265,7 @@ def _getBesideBase(solver):
                 error_message
             )
         raise MustSaveError()
+        # TODO may be do not abort but use a temporary directory
     return path