From e97e4562b1de2cc53824819c0452b096718ed0ad Mon Sep 17 00:00:00 2001
From: Joe Rickerby <joerick@mac.com>
Date: Tue, 4 Aug 2026 11:52:22 +0100
Subject: [PATCH] add tests

---
 cibuildwheel/options.py                       |   8 +-
 ...ns_toml_test.py => options_reader_test.py} | 109 ++++++++++++++++++
 2 files changed, 114 insertions(+), 3 deletions(-)
 rename unit_test/{options_toml_test.py => options_reader_test.py} (88%)

diff --git a/cibuildwheel/options.py b/cibuildwheel/options.py
index 014d501c..2345f18d 100644
--- a/cibuildwheel/options.py
+++ b/cibuildwheel/options.py
@@ -450,7 +450,7 @@ def parse_inherit(config: str | dict[str, str] | None) -> dict[str, InheritRule]
 
     if isinstance(config, str):
         parsed = parse_kw_string(config, default_kw_value="append")
-        inherit_dict = {k: "".join(v).upper() for k, v in parsed.items()}
+        inherit_dict = {k: "".join(v) for k, v in parsed.items()}
     elif isinstance(config, dict):
         inherit_dict = config
     else:
@@ -523,7 +523,7 @@ class OptionsReader:
         Raises an error if an option with this name is not allowed in the
         [tool.cibuildwheel] section of a config file.
         """
-        allowed_option_names = self.default_options.keys() | PLATFORMS | {"overrides"}
+        allowed_option_names = self.default_options.keys() | PLATFORMS | {"inherit", "overrides"}
 
         if name not in allowed_option_names:
             msg = f"Option {name!r} not supported in a config file."
@@ -542,7 +542,9 @@ class OptionsReader:
             msg = f"{name!r} is not allowed in {disallowed_platform_options}"
             raise OptionsReaderError(msg)
 
-        allowed_option_names = self.default_options.keys() | self.default_platform_options.keys()
+        allowed_option_names = (
+            self.default_options.keys() | self.default_platform_options.keys() | {"inherit"}
+        )
 
         if name not in allowed_option_names:
             msg = f"Option {name!r} not supported in the {self.platform!r} section"
diff --git a/unit_test/options_toml_test.py b/unit_test/options_reader_test.py
similarity index 88%
rename from unit_test/options_toml_test.py
rename to unit_test/options_reader_test.py
index dc14d392..140b335c 100644
--- a/unit_test/options_toml_test.py
+++ b/unit_test/options_reader_test.py
@@ -1,3 +1,5 @@
+"""Tests for reading and resolving configuration options."""
+
 from __future__ import annotations
 
 import shlex
@@ -5,6 +7,7 @@ from typing import Any, cast
 
 import pytest
 
+from cibuildwheel import errors
 from cibuildwheel.options import (
     EnvironmentFormat,
     InheritRule,
@@ -553,6 +556,112 @@ before-all = ["override2"]
         )
 
 
+def test_global_inherit(tmp_path: Path) -> None:
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+inherit = {audit-command = "append"}
+audit-command = "twine check {wheel}"
+"""
+    )
+
+    options_reader = OptionsReader(pyproject_toml, platform="linux", env={})
+
+    assert (
+        options_reader.get("audit-command", option_format=ListFormat(" && "))
+        == "abi3audit --strict --report {abi3_wheel} && twine check {wheel}"
+    )
+
+
+def test_platform_inherit(tmp_path: Path) -> None:
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+before-all = "global"
+
+[tool.cibuildwheel.linux]
+inherit = {before-all = "prepend"}
+before-all = "linux"
+"""
+    )
+
+    options_reader = OptionsReader(pyproject_toml, platform="linux", env={})
+
+    assert options_reader.get("before-all", option_format=ListFormat(" && ")) == "linux && global"
+
+
+def test_environment_inherit(tmp_path: Path) -> None:
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+before-all = "config"
+"""
+    )
+
+    options_reader = OptionsReader(
+        pyproject_toml,
+        platform="linux",
+        env={
+            "CIBW_BEFORE_ALL": "env",
+            "CIBW_BEFORE_ALL_LINUX": "linux-env",
+            # A key without a value defaults to append.
+            "CIBW_INHERIT": "before-all; before-all-linux: prepend",
+        },
+    )
+
+    assert (
+        options_reader.get("before-all", option_format=ListFormat(" && "))
+        == "linux-env && config && env"
+    )
+
+
+def test_environment_inherit_none_overrides_default_rule(tmp_path: Path) -> None:
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+enable = ["cpython-freethreading"]
+"""
+    )
+    options_reader = OptionsReader(
+        pyproject_toml,
+        platform="linux",
+        env={"CIBW_ENABLE": "pypy", "CIBW_INHERIT": "enable: none"},
+    )
+
+    assert (
+        options_reader.get(
+            "enable", option_format=ListFormat(" "), default_env_rule=InheritRule.APPEND
+        )
+        == "pypy"
+    )
+
+
+def test_invalid_config_inherit_rule(tmp_path: Path) -> None:
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+inherit = {before-all = "invalid"}
+"""
+    )
+
+    with pytest.raises(OptionsReaderError, match="must contain only"):
+        OptionsReader(pyproject_toml, platform="linux", env={})
+
+
+def test_invalid_environment_inherit_rule() -> None:
+    options_reader = OptionsReader(platform="linux", env={"CIBW_INHERIT": "before-all: invalid"})
+
+    with pytest.raises(
+        errors.ConfigurationError, match="Failed to parse CIBW_INHERIT environment variable"
+    ):
+        options_reader.get("before-all", option_format=ListFormat(" && "))
+
+
 def test_audit_command_option(tmp_path: Path, platform: PlatformName) -> None:
     pyproject_toml: Path = tmp_path / "pyproject.toml"
     pyproject_toml.write_text(