Fix crash when exporting requirements in PassthroughEnv (#354)

* Add test for exporting requirements in PassthroughEnv

* Fix crash when exporting requirements in PassthroughEnv

* Adapt fake session to provide Session._runner

* Adapt type stubs to provide Session._runner

* mypy: Remove unused `type: ignore` comment

noxfile.py

@@ -149,7 +149,7 @@ def tests(session: Session, poetry: Optional[str]) -> None:
 def coverage(session: Session) -> None:
     """Produce the coverage report."""
     # Do not use session.posargs unless this is the only session.
-    nsessions = len(session._runner.manifest)  # type: ignore[attr-defined]
+    nsessions = len(session._runner.manifest)
     has_args = session.posargs and nsessions == 1
     args = session.posargs if has_args else ["report"]
 

src/nox_poetry/sessions.py

@@ -197,8 +197,11 @@ def export_requirements(self) -> Path:
         Returns:
             The path to the requirements file.
         """
-        tmpdir = Path(self.session.virtualenv.location) / "tmp"
-        tmpdir.mkdir(exist_ok=True)
+        # Avoid ``session.virtualenv.location`` because PassthroughEnv does not
+        # have it. We'll just create a fake virtualenv directory in this case.
+
+        tmpdir = Path(self.session._runner.envdir) / "tmp"
+        tmpdir.mkdir(exist_ok=True, parents=True)
 
         path = tmpdir / "requirements.txt"
         hashfile = tmpdir / f"{path.name}.hash"

src/nox_poetry/sessions.pyi

@@ -29,6 +29,7 @@ class _PoetrySession:
 class Session:
     poetry: _PoetrySession
     _session: nox.Session
+    _runner: nox.sessions.SessionRunner
     def __init__(self, session: nox.Session) -> None: ...
     def install(self, *args: str, **kwargs: Any) -> None: ...
     @property

tests/functional/test_functional.py

@@ -347,3 +347,15 @@ def test(session: nox_poetry.Session) -> None:
     packages = list_packages(project, test)
 
     assert set(expected) == set(packages)
+
+
+def test_passthrough_env(project: Project) -> None:
+    """It stores requirements even without a virtualenv directory."""
+    # /~https://github.com/cjolowicz/nox-poetry/issues/347
+
+    @nox_poetry.session(venv_backend="none")
+    def test(session: nox_poetry.Session) -> None:
+        """Export the requirements."""
+        session.poetry.export_requirements()
+
+    run_nox_with_noxfile(project, [test], [nox_poetry])

tests/unit/conftest.py

@@ -8,20 +8,20 @@
 from nox.sessions import Session
 
 
-class FakeVirtualenv:
-    """Fake virtual environment."""
+class FakeSessionRunner:
+    """Fake session runner."""
 
     def __init__(self, path: Path) -> None:
         """Initialize."""
-        self.location = str(path)
+        self.envdir = str(path)
 
 
 class FakeSession:
     """Fake session."""
 
     def __init__(self, path: Path) -> None:
         """Initialize."""
-        self.virtualenv = FakeVirtualenv(path)
+        self._runner = FakeSessionRunner(path)
 
     def run_always(self, *args: str, **kargs: Any) -> str:
         """Run."""

tests/unit/test_sessions.py

@@ -116,8 +116,7 @@ def proxy(session: nox.Session) -> nox_poetry.Session:
 
 def test_session_getattr(proxy: nox_poetry.Session) -> None:
     """It delegates to the real session."""
-    # Fixed in /~https://github.com/theacodes/nox/pull/377
-    assert proxy.virtualenv.location  # type: ignore[attr-defined]
+    assert proxy._runner.envdir
 
 
 def test_session_install(proxy: nox_poetry.Session) -> None: