Add skip for missing ARM64 tools

test/test_windows.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import os
+import subprocess
 import textwrap
 
 import pytest
@@ -9,11 +11,38 @@ from . import test_projects, utils
 basic_project = test_projects.new_c_project()
 
 
+def skip_if_no_msvc(arm64=False):
+    programfiles = os.getenv("ProgramFiles(x86)") or os.getenv("ProgramFiles")
+    if not programfiles:
+        pytest.skip("Requires %ProgramFiles(x86)% variable to be set")
+
+    vswhere = os.path.join(programfiles, "Microsoft Visual Studio", "Installer", "vswhere.exe")
+    if not os.path.isfile(vswhere):
+        pytest.skip("Requires Visual Studio installation")
+
+    require = "Microsoft.VisualStudio.Component.VC.Tools.x86.x64"
+    if arm64:
+        require = "Microsoft.VisualStudio.Component.VC.Tools.ARM64"
+
+    if not subprocess.check_output(
+        [
+            vswhere,
+            "-latest",
+            "-prerelease",
+            "-property", "installationPath",
+            "-requires", require,
+        ]
+    ):
+        pytest.skip("Requires ARM64 compiler to be installed")
+
+
 @pytest.mark.parametrize("use_pyproject_toml", [True, False])
 def test_wheel_tag_is_correct_when_using_windows_cross_compile(tmp_path, use_pyproject_toml):
     if utils.platform != "windows":
         pytest.skip("This test is only relevant to Windows")
 
+    skip_if_no_msvc(arm64=True)
+
     if use_pyproject_toml:
         basic_project.files["pyproject.toml"] = textwrap.dedent(
             """