Using FakeArduino for unit testing with platform io

[tickietackie]

Describe the issue
I'm trying to do the same as the guy here #548.
Using FakeArduino native to unit test with platform io, where ArduinoJson is deeply integrated.
I already tried the fix from the issue there, but I suppose sth. changed, that makes it not work anymore, or I missed something.

Troubleshooter report
Here is the report generated by the ArduinoJson Troubleshooter:

ArduinoJson Troubleshooter's report

1. The issue happens at compile time
2. The error is not in the list

Environment
Here is the environment that I'm using':

• Microconroller: NA
• Core/runtime: NA
• IDE: Platform IO and VS Code

Further information
platform.ini file content:

[env:native]
platform = native
test_ignore = embedded
build_flags = -std=gnu++11
lib_deps = 
	ArduinoJson-6.18.5
	ArduinoFake
#lib_archive = false 

Compile output:

lib/ArduinoJson-6.18.5/src/ArduinoJson/Polyfills/pgmspace_generic.hpp:14:10: error: reinterpret_cast from 'const void' to 'const __FlashStringHelper *' is not allowed
  return reinterpret_cast<T>(pgm_read_ptr(p));
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/ArduinoJson-6.18.5/src/ArduinoJson/Deserialization/DeserializationError.hpp:100:12: note: in instantiation of function template specialization 'ArduinoJson6185_F1::pgm_read<const __FlashStringHelper *>' requested here
    return ARDUINOJSON_READ_STATIC_ARRAY(const __FlashStringHelper*, messages,
           ^
lib/ArduinoJson-6.18.5/src/ArduinoJson/Polyfills/static_array.hpp:20:7: note: expanded from macro 'ARDUINOJSON_READ_STATIC_ARRAY'
      pgm_read<type>(name + index)

[bblanchon]

Hi @tickietackie,

I couldn't find the source of FakeArduino, but it seems that pgm_read_ptr() doesn't return the correct type: it should be const void*, but the error message says it's const void.

This is a common bug in cores that emulate the original pgmspace.h header.
It already poped up in #1381, #1442, #1519, #1536, and #1591.
The root of this bug was fixed a year ago in arduino/ArduinoCore-API#118, but many clones are still using the old code.
I invite you to open a PR in the FakeArduino repository.

In the meantime, you can work around this issue by disabling PROGMEM in ArduinoJson by setting ARDUINOJSON_ENABLE_PROGMEM to 0.

Best regards,
Benoit

[tickietackie]

Thx, for the quick response. The workaround works as supposed.

[maxgerhardt]

For completness' sake: This was addresses in the FakeArduino library (FabioBatSilva/ArduinoFake#21) and so one can reference the latest git version

[env:native]
platform = native
build_flags = -std=gnu++11
lib_deps =
     https:/FabioBatSilva/ArduinoFake/archive/refs/heads/master.zip
     bblanchon/ArduinoJson @ ^6.18.5

and that makes that error go away.