chore(ci): split emulation tests per architecture (#1839)

test/conftest.py

@@ -8,12 +8,16 @@ import pytest
 
 from cibuildwheel.util import detect_ci_provider
 
-from .utils import platform
+from .utils import EMULATED_ARCHS, platform
 
 
 def pytest_addoption(parser) -> None:
     parser.addoption(
-        "--run-emulation", action="store_true", default=False, help="run emulation tests"
+        "--run-emulation",
+        action="store",
+        default=None,
+        help="run emulation tests",
+        choices=("all", *EMULATED_ARCHS),
     )
     parser.addoption("--run-podman", action="store_true", default=False, help="run podman tests")
     parser.addoption(

test/test_emulation.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import itertools
 import subprocess
 
 import pytest
@@ -18,9 +19,13 @@ def test_spam():
 
 
 def test(tmp_path, request):
-    if not request.config.getoption("--run-emulation"):
+    archs = request.config.getoption("--run-emulation")
+    if archs is None:
         pytest.skip("needs --run-emulation option to run")
 
+    if archs == "all":
+        archs = " ".join(utils.EMULATED_ARCHS)
+
     project_dir = tmp_path / "project"
     project_with_a_test.generate(project_dir)
 
@@ -30,15 +35,14 @@ def test(tmp_path, request):
         add_env={
             "CIBW_TEST_REQUIRES": "pytest",
             "CIBW_TEST_COMMAND": "pytest {project}/test",
-            "CIBW_ARCHS": "aarch64 ppc64le s390x",
+            "CIBW_ARCHS": archs,
         },
     )
 
     # also check that we got the right wheels
-    expected_wheels = (
-        utils.expected_wheels("spam", "0.1.0", machine_arch="aarch64")
-        + utils.expected_wheels("spam", "0.1.0", machine_arch="ppc64le")
-        + utils.expected_wheels("spam", "0.1.0", machine_arch="s390x")
+    expected_wheels = itertools.chain.from_iterable(
+        utils.expected_wheels("spam", "0.1.0", machine_arch=arch, single_arch=True)
+        for arch in archs.split(" ")
     )
     assert set(actual_wheels) == set(expected_wheels)
 

test/utils.py

@@ -13,8 +13,12 @@ import sys
 from tempfile import TemporaryDirectory
 from typing import Final
 
+from cibuildwheel.architecture import Architecture
 from cibuildwheel.util import CIBW_CACHE_PATH
 
+EMULATED_ARCHS: Final[list[str]] = sorted(
+    arch.value for arch in (Architecture.all_archs("linux") - Architecture.auto_archs("linux"))
+)
 SINGLE_PYTHON_VERSION: Final[tuple[int, int]] = (3, 12)
 
 platform: str
@@ -154,6 +158,7 @@ def expected_wheels(
     python_abi_tags=None,
     include_universal2=False,
     single_python=False,
+    single_arch=False,
 ):
     """
     Returns a list of expected wheels from a run of cibuildwheel.
@@ -237,7 +242,7 @@ def expected_wheels(
         if platform == "linux":
             architectures = [arch_name_for_linux(machine_arch)]
 
-            if machine_arch == "x86_64":
+            if machine_arch == "x86_64" and not single_arch:
                 architectures.append("i686")
 
             if len(manylinux_versions) > 0: