test framework: fix exception on timeout

If the framework wait_for() method actually times out, it tries to return
stdout and stderr by calling the framework methods of those names.
The stdout() method was protected against the message not having been
captured (as is the case on timeout).  Updated the stderr() method to
use the same technique.

Signed-off-by: Mats Wichmann <mats@linux.com>

1 files changed, 9 insertions, 5 deletions

diff --git a/testing/framework/TestCmd.py b/testing/framework/TestCmd.py
index 79b16f5..5759121 100644
--- a/testing/framework/TestCmd.py
+++ b/testing/framework/TestCmd.py
@@ -311,6 +311,7 @@ import time
 import traceback
 from collections import UserList, UserString
 from subprocess import PIPE, STDOUT
+from typing import Optional
 
 IS_WINDOWS = sys.platform == 'win32'
 IS_MACOS = sys.platform == 'darwin'
@@ -1641,7 +1642,7 @@ class TestCmd:
         """
         time.sleep(seconds)
 
-    def stderr(self, run=None):
+    def stderr(self, run=None) -> Optional[str]:
         """Returns the error output from the specified run number.
 
         If there is no specified run number, then returns the error
@@ -1653,10 +1654,13 @@ class TestCmd:
             run = len(self._stderr)
         elif run < 0:
             run = len(self._stderr) + run
-        run = run - 1
-        return self._stderr[run]
+        run -= 1
+        try:
+            return self._stderr[run]
+        except IndexError:
+            return None
 
-    def stdout(self, run=None):
+    def stdout(self, run=None) -> Optional[str]:
         """Returns the stored standard output from a given run.
 
         Args:
@@ -1673,7 +1677,7 @@ class TestCmd:
             run = len(self._stdout)
         elif run < 0:
             run = len(self._stdout) + run
-        run = run - 1
+        run -= 1
         try:
             return self._stdout[run]
         except IndexError: