Pytest fails to find some libraries

While trying to run pytest on the TA-Lib project (and many other projects) it fails to find this library:

cd /usr/ports/finance/py-ta-lib/work-py39/TA-Lib-0.4.26/talib && /usr/bin/env XDG_DATA_HOME=/usr/ports/finance/py-ta-lib/work-py39  XDG_CONFIG_HOME=/usr/ports/finance/py-ta-lib/work-py39  XDG_CACHE_HOME=/usr/ports/finance/py-ta-lib/work-py39/.cache  HOME=/usr/ports/finance/py-ta-lib/work-py39 PATH=/usr/local/libexec/ccache:/usr/ports/finance/py-ta-lib/work-py39/.bin:/home/yuri/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin PKG_CONFIG_LIBDIR=/usr/ports/finance/py-ta-lib/work-py39/.pkgconfig:/usr/local/libdata/pkgconfig:/usr/local/share/pkgconfig:/usr/libdata/pkgconfig MK_DEBUG_FILES=no MK_KERNEL_SYMBOLS=no SHELL=/bin/sh NO_LINT=YES LDSHARED="cc -shared" PYTHONDONTWRITEBYTECODE= PYTHONOPTIMIZE= PREFIX=/usr/local  LOCALBASE=/usr/local  CC="cc" CFLAGS="-O2 -pipe  -fstack-protector-strong -fno-strict-aliasing "  CPP="cpp" CPPFLAGS=""  LDFLAGS=" -fstack-protector-strong " LIBS=""  CXX="c++" CXXFLAGS="-O2 -pipe -fstack-protector-strong -fno-strict-aliasing  "  MANPREFIX="/usr/local" CCACHE_DIR="/tmp/.ccache" BSD_INSTALL_PROGRAM="install  -s -m 555"  BSD_INSTALL_LIB="install  -s -m 0644"  BSD_INSTALL_SCRIPT="install  -m 555"  BSD_INSTALL_DATA="install  -m 0644"  BSD_INSTALL_MAN="install  -m 444" PYTHONPATH=/usr/ports/finance/py-ta-lib/work-py39/stage/usr/local/lib/python3.9/site-packages /usr/local/bin/python3.9 -m pytest -k '' -rs -v -o addopts= 
========================================================================================== test session starts ==========================================================================================
platform freebsd13 -- Python 3.9.16, pytest-7.2.2, pluggy-1.0.0 -- /usr/local/bin/python3.9
cachedir: .pytest_cache
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/usr/ports/finance/py-ta-lib/work-py39/TA-Lib-0.4.26/talib/.hypothesis/examples')
Using --randomly-seed=1501004421
rootdir: /usr/ports/finance/py-ta-lib/work-py39/TA-Lib-0.4.26
plugins: forked-1.4.0, hypothesis-6.70.0, mypy-plugins-1.10.1, cov-2.9.0, xdist-2.5.0, randomly-3.12.0, timeout-2.1.0, rerunfailures-10.1, flaky-3.7.0, env-0.6.2, freezegun-0.4.2, mock-3.10.0
collected 0 items / 6 errors                                                                                                                                                                            

================================================================================================ ERRORS =================================================================================================
________________________________________________________________________________ ERROR collecting talib/test_abstract.py ________________________________________________________________________________
ImportError while importing test module '/usr/ports/finance/py-ta-lib/work-py39/TA-Lib-0.4.26/talib/test_abstract.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/local/lib/python3.9/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
__init__.py:93: in <module>
    from ._ta_lib import (
E   ModuleNotFoundError: No module named 'talib._ta_lib'
__________________________________________________________________________________ ERROR collecting talib/test_data.py __________________________________________________________________________________

talib._ta_lib is installed into a system-wide directory (/usr/local/lib/python3.9/site-packages/talib/_ta_lib.cpython-39.so), and import talib succeeds in Python.

py39-pytest-7.2.2,1
Python-3.9
FreeBSD 13.1

Reproduce the supplied pytest command and inspect collection of talib/test_abstract.py and talib/test_data.py, focusing on why talib._ta_lib is unavailable during collection despite succeeding in a direct Python import. Compare the test runner's import environment with the system-wide site-packages location; done means identifying a reproducible pytest-side cause and a regression test or documented resolution.