Improve error reporting from test_examples

Emit stderr as well as stdout from the example in case of failure

2 files changed, 5 insertions, 5 deletions

diff --git a/tests/test_examples.py b/tests/test_examples.py
index 3c516e1..7fb2ad3 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -21,12 +21,12 @@ class TestExamplesSucceed(unittest.TestCase):
                 # Use it when we finally drop Python 2...
                 path = os.path.join(root, filename)
                 t1 = time.time()
-                rc, stdout = run_exe(path)
+                rc, stdout, stderr = run_exe(path)
                 elapsed = time.time() - t1
                 if EMIT_ELAPSED_TIME:
                     print('{}... elapsed: {}'.format(filename, elapsed))
                 self.assertEqual(
-                    rc, 0, 'example "{}" failed with stdout =\n{}'.format(filename, stdout))
+                    rc, 0, 'example "{}" failed with stdout =\n{}\nstderr =\n{}'.format(filename, stdout, stderr))
 
 
 if __name__ == '__main__':
diff --git a/tests/test_util.py b/tests/test_util.py
index 38dfdf5..a945c29 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -42,7 +42,7 @@ def _bytes2str(b):
 def run_exe(exe_path, args=[], echo=False):
     """ Runs the given executable as a subprocess, given the
         list of arguments. Captures its return code (rc) and stdout and
-        returns a pair: rc, stdout_str
+        returns a tuple: rc, stdout, stderr
     """
     popen_cmd = [exe_path] + args
     if os.path.splitext(exe_path)[1] == '.py':
@@ -50,5 +50,5 @@ def run_exe(exe_path, args=[], echo=False):
     if echo:
       print('[cmd]', ' '.join(popen_cmd))
     proc = subprocess.Popen(popen_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    proc_stdout = proc.communicate()[0]
-    return proc.returncode, _bytes2str(proc_stdout)
+    stdout, stderr = proc.communicate()
+    return proc.returncode, _bytes2str(stdout), _bytes2str(stderr)