--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/filtertraceback.py	Wed Jan 30 11:44:34 2019 -0800
@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+
+# Filters traceback lines from stdin.
+
+from __future__ import absolute_import, print_function
+
+import sys
+
+state = 'none'
+
+for line in sys.stdin:
+    if state == 'none':
+        if line.startswith('Traceback '):
+            state = 'tb'
+
+    elif state == 'tb':
+        if line.startswith('  File '):
+            state = 'file'
+            continue
+
+        elif not line.startswith(' '):
+            state = 'none'
+
+    elif state == 'file':
+        # Ignore lines after "  File "
+        state = 'tb'
+        continue
+
+    print(line, end='')