adding some tests

nox/virtualenv.py

@@ -67,18 +67,21 @@ def find_uv() -> tuple[bool, str]:
     return uv_on_path is not None, "uv"
 
 
-def uv_version() -> str:
+def uv_version() -> version.Version:
     ret = subprocess.run(
         [UV, "--version"],
         check=False,
         text=True,
         capture_output=True,
     )
     if ret.returncode == 0 and ret.stdout:
-        return ret.stdout.strip().lstrip("uv ")
+        return version.Version(ret.stdout.strip().lstrip("uv "))
+    else:
+        logger.info("Failed to establish uv's version.")
+        return version.Version("0.0")
 
 
-def uv_install_python(python_version) -> bool:
+def uv_install_python(python_version: str) -> bool:
     """Attempts to install a given python version with uv"""
     ret = subprocess.run(
         [UV, "python", "install", python_version],
@@ -89,7 +92,7 @@ def uv_install_python(python_version) -> bool:
 
 HAS_UV, UV = find_uv()
 if HAS_UV:
-    UV_PYTHON_SUPPORT = version.Version(uv_version()) >= version.Version("0.3")
+    UV_PYTHON_SUPPORT = uv_version() >= version.Version("0.3")
 
 
 class InterpreterNotFound(OSError):

tests/test_virtualenv.py

@@ -269,6 +269,11 @@ def test_uv_creation(make_one):
     assert venv._check_reused_environment_type()
 
 
+@has_uv
+def test_uv_managed_python(make_one):
+    make_one(interpreter="cpython3.12", venv_backend="uv")
+
+
 def test_constructor_defaults(make_one):
     venv, _ = make_one()
     assert venv.location
@@ -620,6 +625,42 @@ def find_uv_bin():
     assert nox.virtualenv.find_uv() == (found, path)
 
 
+@pytest.mark.parametrize(
+    ["return_code", "stdout", "expected_result"],
+    [
+        (0, "uv 0.2.3", "0.2.3"),
+        (1, None, "0.0"),
+        (1, "uv 9.9.9", "0.0"),
+    ],
+)
+def test_uv_version_error(monkeypatch, return_code, stdout, expected_result):
+    def mock_run(*args, **kwargs):
+        return subprocess.CompletedProcess(
+            args=["uv", "--version"],
+            stdout=stdout,
+            returncode=return_code,
+        )
+
+    monkeypatch.setattr(subprocess, "run", mock_run)
+    assert nox.virtualenv.uv_version() == version.Version(expected_result)
+
+
+@pytest.mark.parametrize(
+    ["requested_python", "expected_result"],
+    [
+        ("3.11", True),
+        ("pypy3.8", True),
+        ("cpython3.9", True),
+        ("python3.12", True),
+        ("nonpython9.22", False),
+        ("java11", False),
+    ],
+)
+@has_uv
+def test_uv_install(requested_python, expected_result):
+    assert nox.virtualenv.uv_install_python(requested_python) == expected_result
+
+
 def test_create_reuse_venv_environment(make_one, monkeypatch):
     # Making the reuse requirement more strict
     monkeypatch.setenv("NOX_ENABLE_STALENESS_CHECK", "1")