allow pytest to default to link_pyqt

link_pyqt now checks for LINK_PYQT_SKIP, allowing pytest env names like
`py36` to work properly without negative conditionals in tox.ini

scripts/link_pyqt.py

@@ -205,6 +205,10 @@ def main():
     args = parser.parse_args()
 
     if args.tox:
+        #workaround for the lack of negative factors in tox.ini
+        if 'LINK_PYQT_SKIP' in os.environ:
+            print('LINK_PYQT_SKIP set, exiting...')
+            sys.exit(0)
         executable = get_tox_syspython(args.path)
     else:
         executable = sys.executable

tox.ini

@@ -13,6 +13,7 @@ skipsdist = true
 setenv =
     QT_QPA_PLATFORM_PLUGIN_PATH={envdir}/Lib/site-packages/PyQt5/plugins/platforms
     PYTEST_QT_API=pyqt5
+    pyqt{,56,571,58,59}: LINK_PYQT_SKIP=true
     pyqt{,56,571,58,59}: QUTE_BDD_WEBENGINE=true
     cov: PYTEST_ADDOPTS=--cov --cov-report xml --cov-report=html --cov-report=
 passenv = PYTHON DISPLAY XAUTHORITY HOME USERNAME USER CI TRAVIS XDG_* QUTE_* DOCKER
@@ -27,7 +28,7 @@ deps =
     pyqt58: PyQt5==5.8.2
     pyqt59: PyQt5==5.9.2
 commands =
-    pyqtlink: {envpython} scripts/link_pyqt.py --tox {envdir}
+    {envpython} scripts/link_pyqt.py --tox {envdir}
     {envpython} -bb -m pytest {posargs:tests}
     cov: {envpython} scripts/dev/check_coverage.py {posargs}