pybricksdev.connections.pybricks: restore PybricksHub.output

This attribute is used in motor test code in pybricks-micropython so
should not be removed.

Fixes: pybricks/support#1037

Author: dlech

CHANGELOG.md

@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Restored `PybricksHub.output` attribute ([support#1037]).
+
+[support#1037]: https://github.com/orgs/pybricks/discussions/1037
+
 ## [1.0.0-alpha.43] - 2023-04-19
 
 ### Added

pybricksdev/connections/pybricks.py

@@ -6,7 +6,7 @@
 import logging
 import os
 import struct
-from typing import Awaitable, Optional, TypeVar
+from typing import Awaitable, List, Optional, TypeVar
 
 import reactivex.operators as op
 import semver
@@ -93,6 +93,16 @@ def __init__(self):
         # REVISIT: this can potentially waste a lot of RAM if not drained
         self._stdout_line_queue = asyncio.Queue()
 
+        # REVISIT: It would be better to be able to subscribe to output instead
+        # of always capturing it even if it is not used. This is currently
+        # used in motor test code in pybricks-micropython.
+        self.output: List[bytes] = []
+        """
+        Contains lines printed to stdout of the hub as a a list of bytes.
+
+        List is reset each time :meth:`run()` is called.
+        """
+
         # prior to Pybricks Profile v1.3.0, NUS was used for stdio
         self._legacy_stdio = False
 
@@ -148,6 +158,8 @@ def _line_handler(self, line: bytes) -> None:
             print(line_str, file=self.log_file)
             return
 
+        self.output.append(line)
+
         if self.print_output:
             print(line_str)
             return
@@ -425,6 +437,7 @@ async def run(
 
         # Reset output buffer
         self.log_file = None
+        self.output = []
         self._stdout_buf.clear()
         self._stdout_line_queue = asyncio.Queue()
         self.print_output = print_output