Handle stdout/stderr/BaseException in import test.

test/runner/importer.py

@@ -3,12 +3,18 @@
 
 from __future__ import absolute_import, print_function
 
+import contextlib
 import imp
 import os
 import re
 import sys
 import traceback
 
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
+
 
 def main():
     """Main program function."""
@@ -16,10 +22,16 @@ def main():
     messages = set()
 
     for path in sys.argv[1:]:
+        capture = Capture()
         try:
             with open(path, 'r') as module_fd:
+                with capture_output(capture):
                     imp.load_module('module_import_test', module_fd, os.path.abspath(path), ('.py', 'r', imp.PY_SOURCE))
-        except Exception as ex:  # pylint: disable=locally-disabled, broad-except
+
+            capture_report(path, capture, messages)
+        except BaseException as ex:  # pylint: disable=locally-disabled, broad-except
+            capture_report(path, capture, messages)
+
             exc_type, _, exc_tb = sys.exc_info()
             message = str(ex)
             results = list(reversed(traceback.extract_tb(exc_tb)))
@@ -61,5 +73,48 @@ def main():
     if messages:
         exit(10)
 
+
+class Capture(object):
+    """Captured output and/or exception."""
+    def __init__(self):
+        self.stdout = StringIO()
+        self.stderr = StringIO()
+
+
+def capture_report(path, capture, messages):
+    """Report on captured output.
+    :type path: str
+    :type capture: Capture
+    :type messages: set[str]
+    """
+    if capture.stdout.getvalue():
+        message = '%s:%d:%d: %s: %s' % (path, 0, 0, 'Output', 'Import resulted in output to stdout.')
+        messages.add(message)
+        print(message)
+
+    if capture.stderr.getvalue():
+        message = '%s:%d:%d: %s: %s' % (path, 0, 0, 'Output', 'Import resulted in output to stderr.')
+        messages.add(message)
+        print(message)
+
+
+@contextlib.contextmanager
+def capture_output(capture):
+    """Capture sys.stdout and sys.stderr.
+    :type capture: Capture
+    """
+    old_stdout = sys.stdout
+    old_stderr = sys.stderr
+
+    sys.stdout = capture.stdout
+    sys.stderr = capture.stderr
+
+    try:
+        yield
+    finally:
+        sys.stdout = old_stdout
+        sys.stderr = old_stderr
+
+
 if __name__ == '__main__':
     main()