Update regression_test.py (#80)

* Update regression_test.py

* Update regression_test.py

Author: bakpaul

regression_test.py

@@ -1,5 +1,6 @@
 import os
 import sys
+from pathlib import Path
 
 #example of use:
 # on linux
@@ -11,13 +12,22 @@
 # 0 - script name
 # 1 - regression_test binary path
 # 2 - regression scenes dir
-# 3 - regression references dir
-# 4 - sofa build dir
+# 3 - sofa build dir
+# 4 (optional) - Refrence plugin directory. If not set, will take the parent dir of this file.
+
 
 os.environ["REGRESSION_SCENES_DIR"] = sys.argv[2]
-os.environ["REGRESSION_REFERENCES_DIR"] = sys.argv[3]
 
-os.environ["SOFA_ROOT"] = sys.argv[4]
-os.environ["SOFA_PLUGIN_PATH"] = sys.argv[4] + '/lib'
+os.environ["SOFA_ROOT"] = sys.argv[3]
+os.environ["SOFA_PLUGIN_PATH"] = sys.argv[3] + '/lib'
+
+
+if len(sys.argv) == 5:
+    os.environ["REGRESSION_DIR"] = sys.argv[4]
+else:
+    script_dir = Path( __file__ ).parent.absolute()
+    os.environ["REGRESSION_DIR"] = script_dir
+
+
 
 os.system(sys.argv[1])