Add test for argument passthrough

test/test_from_sdist.py

@@ -175,3 +175,44 @@ def test_internal_config_file_argument(tmp_path, capfd):
     # check that before-all was run
     captured = capfd.readouterr()
     assert "test log statement from before-all 1829" in captured.out
+
+
+def test_argument_passthrough(tmp_path, capfd):
+    basic_project = test_projects.new_c_project()
+
+    # make an sdist of a project
+    sdist_dir = tmp_path / "sdist"
+    sdist_dir.mkdir()
+    sdist_path = make_sdist(basic_project, sdist_dir)
+
+    # make a call that should pass some args through to cibuildwheel
+    # this asks cibuildwheel to print the ppc64le build identifiers
+    process = subprocess.run(
+        [
+            sys.executable,
+            "-m",
+            "cibuildwheel.from_sdist",
+            sdist_path,
+            "--platform",
+            "linux",
+            "--archs",
+            "ppc64le",
+            "--print-build-identifiers",
+        ],
+        env={
+            **os.environ,
+            "CIBW_BUILD": "cp38-*",
+        },
+        check=True,
+        stdout=subprocess.PIPE,
+        universal_newlines=True,
+    )
+
+    # fmt: off
+    assert process.stdout == textwrap.dedent(
+        """
+        cp38-manylinux_ppc64le
+        cp38-musllinux_ppc64le
+        """
+    ).lstrip()
+    # fmt: on