diff --git a/ietf/meeting/views.py b/ietf/meeting/views.py
index 9fe336b55..c1d33e51b 100644
--- a/ietf/meeting/views.py
+++ b/ietf/meeting/views.py
@@ -63,6 +63,7 @@ from ietf.secr.proceedings.utils import handle_upload_file
 from ietf.secr.proceedings.proc_utils import (get_progress_stats, post_process, import_audio_files,
     create_recording)
 from ietf.utils.decorators import require_api_key
+from ietf.utils.log import assertion
 from ietf.utils.mail import send_mail_message, send_mail_text
 from ietf.utils.pipe import pipe
 from ietf.utils.pdf import pdf_pages
@@ -722,7 +723,8 @@ def session_draft_pdf(request, num, acronym):
     pdfmarks.close()
     pdfh, pdfn = mkstemp()
     os.close(pdfh)
-    pipe("gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=" + pdfn + " " + pdf_list + " " + pmn)
+    code, out, err = pipe("gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=" + pdfn + " " + pdf_list + " " + pmn)
+    assertion('code == 0')
 
     pdf = open(pdfn,"r")
     pdf_contents = pdf.read()
diff --git a/ietf/submit/checkers.py b/ietf/submit/checkers.py
index 2c0d6a903..5b928f043 100644
--- a/ietf/submit/checkers.py
+++ b/ietf/submit/checkers.py
@@ -13,7 +13,7 @@ from django.conf import settings
 
 import debug                            # pyflakes:ignore
 
-from ietf.utils.log import log
+from ietf.utils.log import log, assertion
 from ietf.utils.models import VersionInfo
 from ietf.utils.pipe import pipe
 from ietf.utils.test_runner import set_coverage_checking
@@ -206,6 +206,7 @@ class DraftYangChecker(object):
                 code, out, err = pipe(cmd)
                 if code > 0 or len(err.strip()) > 0 :
                     error_lines = err.splitlines()
+                    assertion('len(error_lines) > 0')
                     for line in error_lines:
                         if line.strip():
                             try: