fix: look for uv next to python if it's not on PATH

nox/virtualenv.py

@@ -39,6 +39,21 @@
 _SYSTEM = platform.system()
 
 
+def find_uv() -> str | None:
+    if uv := shutil.which("uv"):
+        return uv
+
+    # Handle `pipx install nox[uv]` by looking for uv next to python.
+    uv = os.path.join(os.path.dirname(sys.executable), "uv")
+    if os.path.exists(uv):
+        return uv
+
+    return None
+
+
+UV = find_uv()
+
+
 class InterpreterNotFound(OSError):
     def __init__(self, interpreter: str) -> None:
         super().__init__(f"Python interpreter {interpreter} not found")
@@ -524,7 +539,7 @@ def create(self) -> bool:
                 cmd.extend(["-p", self._resolved_interpreter])
         elif self.venv_backend == "uv":
             cmd = [
-                "uv",
+                UV or "uv",
                 "venv",
                 "-p",
                 self._resolved_interpreter if self.interpreter else sys.executable,
@@ -560,5 +575,5 @@ def create(self) -> bool:
 OPTIONAL_VENVS = {
     "conda": shutil.which("conda") is not None,
     "mamba": shutil.which("mamba") is not None,
-    "uv": shutil.which("uv") is not None,
+    "uv": UV is not None,
 }