[PATCH v2 1/4] tests/functional: Introduce _console_read()

["Cédric Le Goater" <clg@redhat.com>]

Interaction with the console has been a problem in our avocado
tests. In some cases, the expected string does not match in the
output, causing the test to fail with a timeout. These were worked
around by sleeping before reading the console and even with SSH
connections in some places.

To fix, process the console output char by char and not with
readline. This routine was largely inspired by console_wait() in
tests/vm/basevm.py.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 tests/functional/qemu_test/cmd.py | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/tests/functional/qemu_test/cmd.py b/tests/functional/qemu_test/cmd.py
index cbabb1ceed3c..5bca29d1d721 100644
--- a/tests/functional/qemu_test/cmd.py
+++ b/tests/functional/qemu_test/cmd.py
@@ -12,6 +12,7 @@
 # later.  See the COPYING file in the top-level directory.
 
 import logging
+import re
 import os
 import os.path
 import subprocess
@@ -78,6 +79,23 @@ def run_cmd(args):
 def is_readable_executable_file(path):
     return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
 
+def _console_read(vm, expect):
+    console_logger = logging.getLogger('console')
+    output = ""
+    while True:
+        data = vm.console_socket.recv(1)
+        if not data:
+            break
+        output += data.decode("latin1")
+        if expect in output:
+            break
+        if "\r" in output or "\n" in output:
+            lines = re.split("[\r\n]", output)
+            if lines[0]:
+                console_logger.debug(lines[0])
+            output = lines.pop()
+    return output
+
 def _console_interaction(test, success_message, failure_message,
                          send_string, keep_sending=False, vm=None):
     assert not keep_sending or send_string
@@ -98,12 +116,12 @@ def _console_interaction(test, success_message, failure_message,
             continue
 
         try:
-            msg = console.readline().decode().strip()
+            msg = _console_read(vm, success_message)
         except UnicodeDecodeError:
             msg = None
         if not msg:
             continue
-        console_logger.debug(msg)
+        console_logger.debug('found "%s"', msg)
         if success_message is None or success_message in msg:
             break
         if failure_message and failure_message in msg:
-- 
2.47.0