diff --git a/tools/test_android_cts.py b/tools/test_android_cts.py
index b4af1f1..56fca2d 100755
--- a/tools/test_android_cts.py
+++ b/tools/test_android_cts.py
@@ -214,7 +214,7 @@
   assert args.tool in ['jack', 'dx', 'd8']
 
   jack_option = 'ANDROID_COMPILE_WITH_JACK=' \
-      + 'true' if args.tool == 'jack' else 'false'
+      + ('true' if args.tool == 'jack' else 'false')
 
   alt_jar_option = ''
   if args.tool == 'd8':