Allow passing positional arguments to nox sessions

All sessions can now take positional arguments, which will be forwarded
to the command run by the session. This is usually very useful to check
individual files, or pass extra arguments, like:

nox -R -s pytest_max -- -s tests/my/test_this.py

Sessions will not process the pre-defined files when positional
arguments are passed, so when using positional arguments you should
always include paths to check, except for pytest_xxx sessions, which
still if files are omitted, all files will be processed, so it can be
used to use custom options only too. For example:

nox -R -s pytest_max -- -sx

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

noxfile.py

@@ -53,8 +53,9 @@ def formatting(session: nox.Session, install_deps: bool = True) -> None:
     if install_deps:
         session.install(*FMT_DEPS)
 
-    session.run("black", "--check", *source_file_paths(session))
-    session.run("isort", "--check", *source_file_paths(session))
+    paths = source_file_paths(session)
+    session.run("black", "--check", *paths)
+    session.run("isort", "--check", *paths)
 
 
 @nox.session
@@ -65,13 +66,6 @@ def mypy(session: nox.Session, install_deps: bool = True) -> None:
         # fast local tests with `nox -R -e mypy`.
         session.install("-e", ".", "mypy", *PYTEST_DEPS)
 
-    # Since we use other packages in the frequenz namespace, we need to run the
-    # checks for frequenz.sdk from the installed package instead of the src
-    # directory.
-    mypy_paths = [
-        path for path in source_file_paths(session) if not path.startswith("src")
-    ]
-
     mypy_cmd = [
         "mypy",
         "--ignore-missing-imports",
@@ -83,9 +77,21 @@ def mypy(session: nox.Session, install_deps: bool = True) -> None:
         "--strict",
     ]
 
+    # If we have session arguments, we just use those...
+    if session.posargs:
+        session.run(*mypy_cmd, *session.posargs)
+        return
+
     # Runs on the installed package
     session.run(*mypy_cmd, "-p", "frequenz.sdk")
+
     # Runs on the rest of the source folders
+    # Since we use other packages in the frequenz namespace, we need to run the
+    # checks for frequenz.sdk from the installed package instead of the src
+    # directory.
+    mypy_paths = [
+        path for path in source_file_paths(session) if not path.startswith("src")
+    ]
     session.run(*mypy_cmd, *mypy_paths)
 
 
@@ -97,10 +103,11 @@ def pylint(session: nox.Session, install_deps: bool = True) -> None:
         # fast local tests with `nox -R -e pylint`.
         session.install("-e", ".", "pylint", *PYTEST_DEPS)
 
+    paths = source_file_paths(session)
     session.run(
         "pylint",
         "--extension-pkg-whitelist=pydantic",
-        *source_file_paths(session),
+        *paths,
     )
 
 
@@ -110,12 +117,14 @@ def docstrings(session: nox.Session, install_deps: bool = True) -> None:
     if install_deps:
         session.install(*DOCSTRING_DEPS, "toml")
 
-    session.run("pydocstyle", *source_file_paths(session))
+    paths = source_file_paths(session)
+    session.run("pydocstyle", *paths)
 
     # Darglint checks that function argument and return values are documented.
     # This is needed only for the `src` dir, so we exclude the other top level
-    # dirs that contain code.
-    darglint_paths = filter(
+    # dirs that contain code, unless some paths were specified by argument, in
+    # which case we use those untouched.
+    darglint_paths = session.posargs or filter(
         lambda path: not (path.startswith("tests") or path.startswith("benchmarks")),
         source_file_paths(session),
     )
@@ -158,4 +167,5 @@ def _pytest_impl(
         "--cov=frequenz.sdk",
         "--cov-report=term",
         f"--cov-report=html:.htmlcov-{max_or_min_deps}",
+        *session.posargs,
     )