Test enable groups as specified by PR labels (#2357)

* Allow CIBW_ENABLE to control the wheels built in testing

* Set CIBW_ENABLE using PR labels

* Add docs

* Build everything on the main branch

* Add CIBW_ENABLE=all option

This was mostly for use in the `main` building case, because otherwise it's maybe a bit too easy to forget to update this file when adding an enable group

* Remove dead code

* Make unit tests robust to the value of CIBW_ENABLE

* Fix tests that explicitly choose pypy

* Fix test expectation

* Don't expect impossible wheels in expected_wheels

* Simplify logic in expected_wheels

* CircleCI- run with CIBW_ENABLE=all only on the main branch

* Azure pipelines - run with CIBW_ENABLE=all on main branch

* Update gitlab to run CIBW_ENABLE=all on main

* Set CIBW_ENABLE=all on travis - it only runs on main anyway

* Fix job name error on CircleCI

* Fix tests for graalpy

* Update the test configuration to use the label

* Remove duplication of default value. Make it affect sample build too

* Move the action to after deps are installed

* GraalPy workaround for this assumption

* Make unit test resilient to changing CIBW_ENABLE

test/conftest.py

@@ -1,4 +1,5 @@
 import json
+import os
 import subprocess
 from collections.abc import Generator
 
@@ -12,6 +13,9 @@ from cibuildwheel.venv import find_uv
 
 from .utils import EMULATED_ARCHS, platform
 
+# default to just cpython
+DEFAULT_CIBW_ENABLE = "cpython-freethreading cpython-prerelease cpython-experimental-riscv64"
+
 
 def pytest_addoption(parser: pytest.Parser) -> None:
     parser.addoption(
@@ -29,6 +33,8 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         help="macOS cp38 uses the universal2 installer",
     )
 
+    os.environ.setdefault("CIBW_ENABLE", DEFAULT_CIBW_ENABLE)
+
 
 def docker_warmup(request: pytest.FixtureRequest) -> None:
     machine = request.config.getoption("--run-emulation", default=None)