Fix failure when running within a UV venv activated shell (#66)

.pre-commit-config.yaml

@@ -23,7 +23,6 @@ repos:
     rev: "2.1.3"
     hooks:
       - id: pyproject-fmt
-        additional_dependencies: ["tox>=4.15"]
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: "v0.4.9"
     hooks:

src/tox_uv/_venv.py

@@ -111,6 +111,7 @@ def venv_dir(self) -> Path:
     @property
     def environment_variables(self) -> dict[str, str]:
         env = super().environment_variables
+        env.pop("UV_PYTHON", None)  # UV_PYTHON takes precedence over VIRTUAL_ENV
         env["VIRTUAL_ENV"] = str(self.venv_dir)
         return env
 

tests/test_tox_uv_venv.py

@@ -11,6 +11,7 @@
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
+    import pytest
     from tox.pytest import ToxProjectCreator
 
 
@@ -142,3 +143,12 @@ def test_uv_env_python_not_in_path(tox_project: ToxProjectCreator) -> None:
     tox_ini = project.path / "tox.ini"
     assert tox_ini.is_file()
     subprocess.check_call([sys.executable, "-m", "tox", "-c", tox_ini], env=env)
+
+
+def test_uv_python_set(tox_project: ToxProjectCreator, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("UV_PYTHON", sys.executable)
+    project = tox_project({
+        "tox.ini": "[testenv]\npackage=skip\ndeps=setuptools\ncommands=python -c 'import setuptools'"
+    })
+    result = project.run("-vv")
+    result.assert_success()