diff --git a/buildingspy/development/regressiontest.py b/buildingspy/development/regressiontest.py
index 0debe059..c29411dd 100644
--- a/buildingspy/development/regressiontest.py
+++ b/buildingspy/development/regressiontest.py
@@ -257,14 +257,7 @@ def __init__(
         self._rootPackage = os.path.join(self._libHome, 'Resources', 'Scripts', 'Dymola')
 
         # Set the reference results directory
-        if dir_ref is None:
-            self.dir_ref = os.path.join(
-                self._libHome, 'Resources', 'ReferenceResults', 'Dymola'
-            )
-        else:
-            self.dir_ref = dir_ref
-        if not os.path.exists(self.dir_ref):
-            os.makedirs(self.dir_ref)
+        self.dir_ref = dir_ref
 
         # Set the tool
         if tool in ['dymola', 'omc', 'optimica', 'jmodelica']:
@@ -437,6 +430,13 @@ def setLibraryRoot(self, rootDir):
         self._rootPackage = os.path.join(self._libHome, 'Resources', 'Scripts', 'Dymola')
         self.isValidLibrary(self._libHome)
 
+        if self.dir_ref is None:
+            self.dir_ref = os.path.join(
+                self._libHome, 'Resources', 'ReferenceResults', 'Dymola'
+            )
+        if not os.path.exists(self.dir_ref):
+            os.makedirs(self.dir_ref)
+
     def useExistingResults(self, dirs):
         """ This function allows to use existing results, as opposed to running a simulation.