> Migrates the CScriptNum decode tests into a unit test, and moved some
> changes made in core#14816. Made possible by the integration of
> test_framework unit testing in core#18576. Further extends the original
> test with larger ints, similar to the scriptnum_tests.cpp file. Adds
> test to blocktools.py testing fn create_coinbase() with CScriptNum
> decode.
Backport note:
The functional tests are usually executed individually via a `subprocess`.
This means the `get_srcdir()` function in cdefs.py is able to find the
proper source directory, because the parent directory of the process is
the project root that contains `src/`.
But when we run the new test_framework unit test, the process currently running
is `test_runner.py` itself which is located in the build directory.
So cdefs.py finds the wrong `src/` directory, the one located in the build
directory, which does not contain `consensus.h`.
I fixed this by setting the environment variable `SRCDIR` in `test_runner.py`
before calling the unittest `unittest.TestLoader().loadTestsFromName` machinery
which causes `cdefs.py` to be imported.
This is a backport of core#19082