New feature: --ignore argument in test.py

[andrewleech]

Simply passes the parameter through when building with test.py

Supports and requires ARMmbed/mbed-os#6833

[screamerbg]

@andrewleech Thanks for this. Looking good to me.

@theotherjimmy @cmonr Any concerns?

[theotherjimmy]

@screamerbg @andrewleech We should have the same feature in compile and export, for consistency.

[screamerbg]

Would like to poke @sg- for his take on this.

[screamerbg]

@andrewleech Note that this won't work prior to Mbed OS 5.9 (after ARMmbed/mbed-os#6833 patch is merged), therefore the option help should explicitly mention this.

[sg-]

Is there a use case for this other than ignoring main when running tests? This certainly is a simple solution but would worry about the annoyance of not remembering what file contains the main function.

@bridadan Do you recall the previous thinking around solutions to multiple main functions?

[andrewleech]

I've also used it since to build tests with rtos (--exclude main) and then compile app without rtos (--exclude mbed-os/rtos)

I guess if you're working completely on the command line this just means more typing. I'm using vscode so the command line is saved in its tools settings.

[cmonr]

I like the addition.

[bridadan]

@bridadan Do you recall the previous thinking around solutions to multiple main functions?

I believe the option we suggested at the time was to provide a different entry point for tests. Something like test_main or something instead of main. This could be enabled by specifying an additional define when compiling with mbed test.

One thing to keep in mind with that approach though is that any global static defines in your app's main file would still be brought in for each test (you would pay a RAM/ROM penalty). Short of knowing where that file is and excluding it from the build I don't think there's a way we can prevent that.