Add integration test for emulation

test/conftest.py

@@ -0,0 +1,21 @@
+import pytest
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--run-emulation", action="store_true", default=False, help="run emulation tests"
+    )
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "emulation: mark test requiring qemu binfmt_misc to run")
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--run-emulation"):
+        # --run-emulation given in cli: do not skip emulation tests
+        return
+    skip_emulation = pytest.mark.skip(reason="need --run-emulation option to run")
+    for item in items:
+        if "emulation" in item.keywords:
+            item.add_marker(skip_emulation)

test/test_emulation.py

@@ -0,0 +1,35 @@
+import pytest
+from . import utils
+from . import test_projects
+
+
+project_with_a_test = test_projects.new_c_project()
+
+project_with_a_test.files['test/spam_test.py'] = r'''
+import spam
+
+def test_spam():
+    assert spam.system('python -c "exit(0)"') == 0
+    assert spam.system('python -c "exit(1)"') != 0
+'''
+
+
+@pytest.mark.emulation
+def test(tmp_path):
+    project_dir = tmp_path / 'project'
+    project_with_a_test.generate(project_dir)
+
+    # build and test the wheels
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
+        'CIBW_TEST_REQUIRES': 'pytest',
+        'CIBW_TEST_COMMAND': 'pytest {project}/test',
+        'CIBW_ARCHS': 'aarch64 ppc64le s390x',
+    })
+
+    # 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')
+    )
+    assert set(actual_wheels) == set(expected_wheels)

test/utils.py

@@ -76,7 +76,7 @@ def cibuildwheel_run(project_path, package_dir='.', env=None, add_env=None, outp
 
 
 def expected_wheels(package_name, package_version, manylinux_versions=None,
-                    macosx_deployment_target='10.9'):
+                    macosx_deployment_target='10.9', machine_arch=None):
     '''
     Returns a list of expected wheels from a run of cibuildwheel.
     '''
@@ -85,15 +85,18 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
     # {python tag} and {abi tag} are closely related to the python interpreter used to build the wheel
     # so we'll merge them below as python_abi_tag
 
+    if machine_arch is None:
+        machine_arch = pm.machine()
+
     if manylinux_versions is None:
-        if pm.machine() == 'x86_64':
+        if machine_arch == 'x86_64':
             manylinux_versions = ['manylinux1', 'manylinux2010']
         else:
             manylinux_versions = ['manylinux2014']
 
     python_abi_tags = ['cp35-cp35m', 'cp36-cp36m', 'cp37-cp37m', 'cp38-cp38', 'cp39-cp39']
 
-    if pm.machine() in ['x86_64', 'AMD64', 'x86']:
+    if machine_arch in ['x86_64', 'AMD64', 'x86']:
         python_abi_tags += ['cp27-cp27m', 'pp27-pypy_73', 'pp36-pypy36_pp73', 'pp37-pypy37_pp73']
 
         if platform == 'linux':
@@ -105,9 +108,9 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
         platform_tags = []
 
         if platform == 'linux':
-            architectures = [pm.machine()]
+            architectures = [machine_arch]
 
-            if pm.machine() == 'x86_64' and python_abi_tag.startswith('cp'):
+            if machine_arch == 'x86_64' and python_abi_tag.startswith('cp'):
                 architectures.append('i686')
 
             platform_tags = [