test/py: multiplexed_log.py: Clean up and correct RunAndLog()

The general python documentation for the subprocess class recommends
that run() be used in all cases that it can handle. What we do in
RunAndLog is simple enough that run() is easy to switch to. In fact,
looking at this exposed a problem we have today, which is that we had
combined stdout and stderr but then looked at both stdout and stderr as
if they were separate. Stop combining them.

Signed-off-by: Tom Rini <[email protected]>

1 files changed, 4 insertions, 4 deletions

diff --git a/test/py/multiplexed_log.py b/test/py/multiplexed_log.py
index 63237594bb4..68dc183e463 100644
--- a/test/py/multiplexed_log.py
+++ b/test/py/multiplexed_log.py
@@ -138,10 +138,10 @@ class RunAndLog(object):
         self.logfile.write(self, msg)
 
         try:
-            p = subprocess.Popen(cmd, cwd=cwd,
-                stdin=subprocess.PIPE if stdin else None,
-                stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env)
-            (stdout, stderr) = p.communicate(input=stdin)
+            p = subprocess.run(cmd, cwd=cwd, capture_output=True, input=stdin,
+                               env=env)
+            stdout = p.stdout
+            stderr = p.stderr
             if stdout is not None:
                 stdout = stdout.decode('utf-8')
             if stderr is not None: