Tests might want to look at the whole output from a command execution,
as well as just logging it. Add support for this.

Signed-off-by: John Levon <john.levon@nutanix.com>
---
 tests/functional/qemu_test/cmd.py | 53 +++++++++++++++++++++++++------
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/tests/functional/qemu_test/cmd.py b/tests/functional/qemu_test/cmd.py
index dc5f422b77..c19dfc577f 100644
--- a/tests/functional/qemu_test/cmd.py
+++ b/tests/functional/qemu_test/cmd.py
@@ -45,6 +45,9 @@ def is_readable_executable_file(path):
 # If end of line is seen, with neither @success or @failure
 # return False
 #
+# In both cases, also return the contents of the line (in bytes)
+# up to that point.
+#
 # If @failure is seen, then mark @test as failed
 def _console_read_line_until_match(test, vm, success, failure):
     msg = bytes([])
@@ -76,10 +79,23 @@ def _console_read_line_until_match(test, vm, success, failure):
     except:
         console_logger.debug(msg)
 
-    return done
+    return done, msg
 
 def _console_interaction(test, success_message, failure_message,
                          send_string, keep_sending=False, vm=None):
+    """
+    Interact with the console until either message is seen.
+
+    :param success_message: if this message appears, finish interaction
+    :param failure_message: if this message appears, test fails
+    :param send_string: a string to send to the console before trying
+                        to read a new line
+    :param keep_sending: keep sending the send string each time
+    :param vm: the VM to interact with
+
+    :return: The collected output (in bytes form).
+    """
+
     assert not keep_sending or send_string
     assert success_message or send_string
 
@@ -101,6 +117,8 @@ def _console_interaction(test, success_message, failure_message,
     if failure_message is not None:
         failure_message_b = failure_message.encode()
 
+    out = bytes([])
+
     while True:
         if send_string:
             vm.console_socket.sendall(send_string.encode())
@@ -113,11 +131,17 @@ def _console_interaction(test, success_message, failure_message,
                 break
             continue
 
-        if _console_read_line_until_match(test, vm,
-                                          success_message_b,
-                                          failure_message_b):
+        done, line = _console_read_line_until_match(test, vm,
+                                                    success_message_b,
+                                                    failure_message_b)
+
+        out += line
+
+        if done:
             break
 
+    return out
+
 def interrupt_interactive_console_until_pattern(test, success_message,
                                                 failure_message=None,
                                                 interrupt_string='\r'):
@@ -140,10 +164,12 @@ def interrupt_interactive_console_until_pattern(test, success_message,
     :param failure_message: if this message appears, test fails
     :param interrupt_string: a string to send to the console before trying
                              to read a new line
+
+    :return: The collected output (in bytes form).
     """
     assert success_message
-    _console_interaction(test, success_message, failure_message,
-                         interrupt_string, True)
+    return _console_interaction(test, success_message, failure_message,
+                                interrupt_string, True)
 
 def wait_for_console_pattern(test, success_message, failure_message=None,
                              vm=None):
@@ -155,9 +181,12 @@ def wait_for_console_pattern(test, success_message, failure_message=None,
     :type test: :class:`qemu_test.QemuSystemTest`
     :param success_message: if this message appears, test succeeds
     :param failure_message: if this message appears, test fails
+
+    :return: The collected output (in bytes form).
     """
     assert success_message
-    _console_interaction(test, success_message, failure_message, None, vm=vm)
+    return _console_interaction(test, success_message, failure_message,
+                                None, vm=vm)
 
 def exec_command(test, command):
     """
@@ -168,8 +197,10 @@ def exec_command(test, command):
     :type test: :class:`qemu_test.QemuSystemTest`
     :param command: the command to send
     :type command: str
+
+    :return: The collected output (in bytes form).
     """
-    _console_interaction(test, None, None, command + '\r')
+    return _console_interaction(test, None, None, command + '\r')
 
 def exec_command_and_wait_for_pattern(test, command,
                                       success_message, failure_message=None):
@@ -184,9 +215,13 @@ def exec_command_and_wait_for_pattern(test, command,
     :param command: the command to send
     :param success_message: if this message appears, test succeeds
     :param failure_message: if this message appears, test fails
+
+    :return: The collected output (in bytes form).
     """
     assert success_message
-    _console_interaction(test, success_message, failure_message, command + '\r')
+
+    return _console_interaction(test, success_message, failure_message,
+                                command + '\r')
 
 def get_qemu_img(test):
     test.log.debug('Looking for and selecting a qemu-img binary')
-- 
2.43.0