[OMCSession] add get_version() and get_workdir() (#417)

* this prepares a version of OMCSession which is independend of OMC as
  these functions where the last two which needed sendExpression() in
  basic ModelicaSystem functionality

Co-authored-by: Adeel Asghar <adeel.asghar@liu.se>

Author: syntron

OMPython/ModelicaSystem.py

@@ -352,7 +352,7 @@ def __init__(
             self._session = OMCSessionLocal(omhome=omhome)
 
         # get OpenModelica version
-        version_str = self.sendExpression(expr="getVersion()")
+        version_str = self._session.get_version()
         self._version = self._parse_om_version(version=version_str)
         # set commandLineOptions using default values or the user defined list
         if command_line_options is None:
@@ -514,8 +514,7 @@ def setWorkDirectory(self, work_directory: Optional[str | os.PathLike] = None) -
                 raise IOError(f"{workdir} could not be created")
 
         logger.info("Define work dir as %s", workdir)
-        expr = f'cd("{workdir.as_posix()}")'
-        self.sendExpression(expr=expr)
+        self._session.set_workdir(workdir=workdir)
 
         # set the class variable _work_dir ...
         self._work_dir = workdir

OMPython/OMCSession.py

@@ -759,6 +759,19 @@ def escape_str(value: str) -> str:
         """
         return value.replace("\\", "\\\\").replace('"', '\\"')
 
+    def get_version(self) -> str:
+        """
+        Get the OM version.
+        """
+        return self.sendExpression("getVersion()", parsed=True)
+
+    def set_workdir(self, workdir: OMCPath) -> None:
+        """
+        Set the workdir for this session.
+        """
+        exp = f'cd("{workdir.as_posix()}")'
+        self.sendExpression(exp)
+
     def omcpath(self, *path) -> OMCPath:
         """
         Create an OMCPath object based on the given path segments and the current OMCSession* class.