diff --git a/voltha/adapters/adtran_onu/Makefile b/voltha/adapters/adtran_onu/Makefile
index e1f27ee..ff9a598 100644
--- a/voltha/adapters/adtran_onu/Makefile
+++ b/voltha/adapters/adtran_onu/Makefile
@@ -6,7 +6,7 @@
 VENVDIR=$(WORKING_DIR)venv
 TESTDIR=$(WORKING_DIR)test
 
-ADD_TO_PYTHONPATH := export PYTHONPATH=$(PYTHONPATH):$(VOLTHA_DIR)/protos/third_party;
+PYTHONPATH := $(PYTHONPATH):$(VOLTHA_DIR)protos/third_party;
 IN_VENV=. '$(VENVDIR)/bin/activate';
 
 PROFILING=--profile-svg
@@ -16,7 +16,7 @@
 PROFILING=
 endif
 
-RUN_PYTEST=$(IN_VENV) $(ADD_TO_PYTHONPATH) py.test -vvlx $(PROFILING) --cov=$(WORKING_DIR) --cov-report term-missing --cov-report html
+RUN_PYTEST=$(IN_VENV) PYTHONPATH=$(PYTHONPATH) py.test -vvlx $(PROFILING) --cov=$(WORKING_DIR) --cov-report term-missing --cov-report html
 
 $(VENVDIR):
 	@virtualenv -p python2 $(VENVDIR)