diff --git a/test/fuzz/test_runner.py b/test/fuzz/test_runner.py
--- a/test/fuzz/test_runner.py
+++ b/test/fuzz/test_runner.py
@@ -127,9 +127,13 @@
             corpus_path,
         ]
         logging.debug('Run {} with args {}'.format(t, args))
-        output = subprocess.run(
-            args, check=True, stderr=subprocess.PIPE, universal_newlines=True).stderr
+        result = subprocess.run(
+            args,
+            stderr=subprocess.PIPE,
+            universal_newlines=True)
+        output = result.stderr
         logging.debug('Output: {}'.format(output))
+        result.check_returncode()
         if not export_coverage:
             continue
         for line in output.splitlines():