[self testsuite] testpep561.py::PEP561Suite tests fail against pip 21.3

[stanislavlevin]

As of 21.3 pip

Remove the --build-dir option and aliases, one last time. (pypa/pip#10485)

https://pip.pypa.io/en/stable/news/#v21-3

So, all the tests in test/testpep561.py::PEP561Suite fail.

Similar issue pip issue: pypa/pip#10576
Actually, -b was no-op for over 1 year.

Tests log:

...
________________________ testTypedPkgNamespaceRegImport ________________________
[gw5] linux -- Python 3.9.7 /usr/src/RPM/BUILD/python3-module-mypy-0.910/.tox/py
3/bin/python
data: /usr/src/RPM/BUILD/python3-module-mypy-0.910/test-data/unit/pep561.test:15
9:
../../RPM/BUILD/python3-module-mypy-0.910/mypy/test/testpep561.py:43: in run_cas
e
    test_pep561(test_case)
../../RPM/BUILD/python3-module-mypy-0.910/mypy/test/testpep561.py:119: in test_p
ep561
    install_package(pkg, python_executable, use_pip, editable)
../../RPM/BUILD/python3-module-mypy-0.910/mypy/test/testpep561.py:90: in install
_package
    raise Exception(proc.stdout.decode('utf-8') + proc.stderr.decode('utf-8'))
E   Exception: 
E   Usage:   
E     /usr/src/tmp/tmpokx9973n/bin/python -m pip install [options] <requirement specifier> [package-index-options] ...
E     /usr/src/tmp/tmpokx9973n/bin/python -m pip install [options] -r <requirements file> [package-index-options] ...
E     /usr/src/tmp/tmpokx9973n/bin/python -m pip install [options] [-e] <vcs project url> ...
E     /usr/src/tmp/tmpokx9973n/bin/python -m pip install [options] [-e] <local project path> ...
E     /usr/src/tmp/tmpokx9973n/bin/python -m pip install [options] <archive url/path> ...
E   
E   no such option: -b
...
=========================== short test summary info ============================
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgNoSitePkgsIgnoredImports
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgSimple
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgSimplePackageSearchPath
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkg_config_nositepackages
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkg_args_nositepackages
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgStubs
FAILED mypy/test/testpep561.py::PEP561Suite::testStubPrecedence
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgSimpleEditable
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgNamespaceImportFrom
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgNamespaceImportAs
FAILED mypy/test/testpep561.py::PEP561Suite::testTypedPkgNamespaceRegImport
=========== 11 failed, 8961 passed, 598 skipped in 775.91s (0:12:55) ===========

[stanislavlevin]

As a trick env variable PIP_BUILD may be used, which is just ignored by new pip 21.3 and honored by previous versions, but it seems -b is not needed.

[emmatyping]

Thanks for catching that! I made #11356 to fix this.