Update setuptools testing

pyproject.toml

@@ -3,7 +3,8 @@ backends = [
   "maturin",
   "meson-python @ git+https://github.com/mgorny/meson-python@freethreading-limited-api",
   "scikit-build-core",
-  "setuptools",
+  "setuptools @ git+https://github.com/ngoldbaum/setuptools@abi3.abi3t",
+  "packaging @ git+https://github.com/ngoldbaum/packaging@abi3.abi3t",
 ]
 build-tools = [
   "cython @ git+https://github.com/cython/cython@freethreading-limited-api-preview",

setuptools/c/pyproject.toml

@@ -1,6 +1,9 @@
 [build-system]
 build-backend = "setuptools.build_meta"
-requires = ["setuptools"]
+requires = [
+  "setuptools@git+https://github.com/ngoldbaum/setuptools@abi3.abi3t",
+  "packaging@git+https://github.com/ngoldbaum/packaging@abi3.abi3t",
+]
 
 [project]
 name = "limited-api"

setuptools/c/setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+py_limited_api = cp315

setuptools/cython/pyproject.toml

@@ -1,13 +1,17 @@
 [build-system]
 build-backend = "setuptools.build_meta"
 requires = [
-  "setuptools",
+  "setuptools@git+https://github.com/ngoldbaum/setuptools@abi3.abi3t",
+  "packaging@git+https://github.com/ngoldbaum/packaging@abi3.abi3t",
   "cython@git+https://github.com/cython/cython@freethreading-limited-api-preview",
 ]
 
 [project]
 name = "limited-api"
 version = "1.2.3"
+dependencies = [
+  "setuptools@git+https://github.com/ngoldbaum/setuptools@abi3.abi3t"
+]
 
 [[tool.setuptools.ext-modules]]
 name = "limited"

setuptools/cython/setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+py_limited_api = cp315

tests/test_wheel.py

@@ -4,7 +4,7 @@
 from build import ProjectBuilder
 import pytest
 
-from contextlib import contextmanager
+from contextlib import contextmanager, nullcontext
 from pathlib import Path
 import os
 import subprocess
@@ -75,12 +75,20 @@ def test_install(test_case: str, tmp_path: Path, subtests) -> None:
     ):
         dist_path = builder.build("wheel", tmp_path)
 
-    with subtests.test(msg="wheel has 'abi3.abi3t' tag"):
-        with subxfail(
-            build_system != "meson-python",
-            reason="Only meson-python fork builds abi3.abi3t",
-        ):
-            assert "abi3.abi3t" in Path(dist_path).name
+    with subtests.test(msg="wheel has correct ABI tag"):
+        if IS_FREETHREADING or build_system == "meson_python":
+            context = subxfail(
+                build_system not in ("meson-python", "setuptools"),
+                reason="Only meson-python and setuptools forks build abi3.abi3t",
+            )
+        else:
+            context = nullcontext()
+        with context:
+            if ((build_system == "setuptools" and IS_FREETHREADING) or
+                build_system == "meson_python"):
+                assert "abi3.abi3t" in Path(dist_path).name
+            else:
+                assert "abi3" in Path(dist_path).name
 
     subprocess.run([sys.executable, "-m", "venv", tmp_path / "venv"], check=True)
     python_exe = "python.exe" if os.name == "nt" else "python"