Unit testing with unity fails on Windows because of Serial.end

[aaronfultonnz]

I've been using the Unity framework for testing code for the RP2040 MCU on Arduino, however I have run into an issue with tests completing cleanly. I've narrowed this down to the call to Serial.end() in void unityOutputComplete(void) { Serial.end(); } [platformio/test/runners/unity.py] which then gets compiled into unity_config.cpp

This causes:

• Final test results to not always come through
• A permission denied error (due to closed serial port)
• Prevents the MCU from software reboots (because the serial is not running), and thus requires manual intervention to run subsequent tests.

I want to know if Serial.end() is necessary here at all? Is there any downside to leaving the Serial running at the end of the test (for Arudino this will sit in loop(), which is normal behavior).

[maxgerhardt]

Just FYI, the default Arduino implementation of the Unity handlers are in

platformio-core/platformio/test/runners/unity.py

Lines 126 to 130 in d6141b3

	#include <Arduino.h>
	void unityOutputStart(unsigned long baudrate) { Serial.begin(baudrate); }
	void unityOutputChar(unsigned int c) { Serial.write(c); }
	void unityOutputFlush(void) { Serial.flush(); }
	void unityOutputComplete(void) { Serial.end(); }

And you can always supply your own ones that don't do this:

https://docs.platformio.org/en/latest/advanced/unit-testing/frameworks/unity.html#custom-unity-config-h

https://github.com/platformio/platformio-examples/tree/develop/unit-testing/stm32cube/test