… error

The typeshed stubs for logging.basicConfig don't include the encoding
parameter in the handlers overload. The encoding is already set on the
WatchedFileHandler itself (line 22), so passing it again to basicConfig
is redundant and causes a mypy call-overload error.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The PR added _setup_proxy_environment() in _on_image_relation_joined.
The test was using a plain MagicMock() for BuilderConfig.from_charm,
causing build_config.proxy to be a MagicMock. When passed to
_setup_proxy_environment, assigning it to os.environ raises TypeError.

Fix: return a mock config with proxy=None so the proxy setup is skipped.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The Observer stored self.charm typed as ops.CharmBase, but called
_setup_proxy_environment which is defined on GithubRunnerImageBuilderCharm.
Use TYPE_CHECKING to import the concrete type and annotate the constructor
parameter correctly, resolving the attr-defined mypy error.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…onment

The method is called from image.Observer (outside the charm class), so
it should be public. Renamed from _setup_proxy_environment to
setup_proxy_environment to avoid the pylint protected-access warning.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>