diff --git a/python/qrcodegen-batch-test.py b/python/qrcodegen-batch-test.py
index bce48bf..f0d3663 100644
--- a/python/qrcodegen-batch-test.py
+++ b/python/qrcodegen-batch-test.py
@@ -30,8 +30,8 @@ if sys.version_info.major < 3:
 
 
 CHILD_PROGRAMS = [
-	["python2", "../python/qrcodegen-worker.py"],  # Python 2 program
-	["python3", "../python/qrcodegen-worker.py"],  # Python 3 program
+	["python2", "-B", "../python/qrcodegen-worker.py"],  # Python 2 program
+	["python3", "-B", "../python/qrcodegen-worker.py"],  # Python 3 program
 	["java", "-cp", "../java/src/main/java", "-ea:io.nayuki.qrcodegen...", "io/nayuki/qrcodegen/QrCodeGeneratorWorker"],  # Java program
 	["node", "../typescript/qrcodegen-worker.js"],  # TypeScript program
 	["../c/qrcodegen-worker"],  # C program