diff --git a/test/Makefile.am b/test/Makefile.am
index 355d7c9..0d74b32 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -33,7 +33,7 @@ endif
 # Optional python bindings
 if ENABLE_PYTHON_BINDING
   TEST_PYTHON_SCRIPT = test_python.py
-  TEST_PYTHON_ENV    = PYTHONPATH=$(top_builddir)/pyext/build:$PYTHONPATH
+  TEST_PYTHON_ENV    = PYTHONPATH=$(top_builddir)/pyext/build:$(PYTHONPATH)
 endif
 
 # Include directories