diff --git a/src/glsl/tests/Makefile.am b/src/glsl/tests/Makefile.am
index c1c74e75b57..d2facbaabb8 100644
--- a/src/glsl/tests/Makefile.am
+++ b/src/glsl/tests/Makefile.am
@@ -7,6 +7,10 @@ INC = \
 AM_CFLAGS =  $(INC)
 AM_CXXFLAGS = $(INC)
 
+TESTS_ENVIRONMENT= \
+	export PYTHON2=$(PYTHON2); \
+	export PYTHON_FLAGS=$(PYTHON_FLAGS);
+
 TESTS = \
 	optimization-test \
 	ralloc-test \
diff --git a/src/glsl/tests/optimization-test b/src/glsl/tests/optimization-test
index 0c130be1379..363c6ccda56 100755
--- a/src/glsl/tests/optimization-test
+++ b/src/glsl/tests/optimization-test
@@ -8,12 +8,12 @@ for test in `find . -iname '*.opt_test'`; do
     echo -n "Testing $test..."
     (cd `dirname "$test"`; ./`basename "$test"`) > "$test.out" 2>&1
     total=$((total+1))
-    if ./compare_ir "$test.expected" "$test.out" >/dev/null 2>&1; then
+    if $PYTHON2 $PYTHON_FLAGS ./compare_ir "$test.expected" "$test.out" >/dev/null 2>&1; then
         echo "PASS"
         pass=$((pass+1))
     else
         echo "FAIL"
-        ./compare_ir "$test.expected" "$test.out"
+        $PYTHON2 $PYTHON_FLAGS ./compare_ir "$test.expected" "$test.out"
     fi
 done