Fix pytest invocation

`pytest` was invoked with all source and extra paths, but it shouldn't.
Instead the path should be configured by the user in pyproject.toml.

If the user pass any positional arguments to the `pytest` sessions, then
those arguments will be forwarded verbatim to `pytest`.

Since `pytest` works with the default path `tests`, we leave that in the
extra paths in case the user is not defining it explicitly in the
configuration, but for more esoteric setups, the test paths should be
automatically added.

This commit also updates the default configuration for `api` to replace
`tests` with `pytests` in the extra paths (even when the user should
configure it explicitly, we want to remove `tests` as it might be for
something else) and also to replace `src` with `py` in the source paths.

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

Author: llucax

src/frequenz/repo/config/nox/default.py

@@ -27,7 +27,10 @@
 method.
 """
 
+import dataclasses
+
 from . import config as _config
+from . import util
 
 common_command_options: _config.CommandsOptions = _config.CommandsOptions(
     black=[
@@ -86,8 +89,16 @@
 api_command_options: _config.CommandsOptions = common_command_options.copy()
 """Default command-line options for APIs."""
 
-api_config: _config.Config = common_config.copy()
-"""Default configuration for APIs."""
+api_config: _config.Config = dataclasses.replace(
+    common_config,
+    source_paths=list(util.replace(common_config.source_paths, {"src": "py"})),
+    extra_paths=list(util.replace(common_config.extra_paths, {"tests": "pytests"})),
+)
+"""Default configuration for APIs.
+
+Same as `common_config`, but with `source_paths` replacing `"src"` with `"py"`
+and `extra_paths` replacing `"tests"` with `"pytests"`.
+"""
 
 actor_command_options: _config.CommandsOptions = common_command_options.copy()
 """Default command-line options for actors."""

src/frequenz/repo/config/nox/session.py

@@ -145,7 +145,7 @@ def _pytest_impl(
     session: nox.Session, max_or_min_deps: str  # pylint: disable=unused-argument
 ) -> None:
     conf = config.get()
-    session.run("pytest", *conf.opts.pytest, *conf.path_args(session))
+    session.run("pytest", *conf.opts.pytest, *session.posargs)
 
     # pylint: disable=fixme
     # TODO: Implement coverage reporting, we need to research this a bit and it

src/frequenz/repo/config/nox/util.py

@@ -10,7 +10,7 @@
 
 import pathlib
 import tomllib
-from collections.abc import Iterable
+from collections.abc import Iterable, Mapping, Set
 from typing import TypeVar
 
 _T = TypeVar("_T")
@@ -31,6 +31,27 @@ def flatten(iterables: Iterable[Iterable[_T]], /) -> Iterable[_T]:
     return (item for sublist in iterables for item in sublist)
 
 
+def replace(iterable: Iterable[_T], replacements: Mapping[_T, _T], /) -> Iterable[_T]:
+    """Replace elements in an iterable.
+
+    Args:
+        iterable: The iterable to replace elements in.
+        old: The elements to replace.
+        new: The elements to replace with.
+
+    Returns:
+        An iterable with the elements in `iterable` replaced.
+
+    Example:
+        >>> assert list(replace([1, 2, 3], old={1, 2}, new={4, 5})) == [4, 5, 3]
+    """
+    for item in iterable:
+        if item in replacements:
+            yield replacements[item]
+        else:
+            yield item
+
+
 def existing_paths(paths: Iterable[str], /) -> Iterable[pathlib.Path]:
     """Filter paths to only leave valid paths that exist.