extra_template_vars plugin hook

[simonw]

Refs #541

[simonw]

I'm getting this weird failure again:

self = <click.testing.CliRunner object at 0x7f4295b7bd30>
    @contextlib.contextmanager
    def isolated_filesystem(self):
        """A context manager that creates a temporary folder and changes
        the current working directory to it for isolated filesystem tests.
        """
>       cwd = os.getcwd()
E       FileNotFoundError: [Errno 2] No such file or directory

I saw this the other day too, but managed to avoid it by skipping any code that messed around with temporary files.

Baffled as to why this is showing up now, as none of the changes I'm making here have any relevance to the way temporary files are created or the current working directory is set.

I understand the root cause here to be that the working directory for the tests was deleted while the tests were still running, which would seem to indicate that something to do with a tmpdir fixture is at fault.

[simonw]

I bet that error is something to do with this:

datasette/tests/test_plugins.py

Lines 195 to 197 in e06e083

	for client in make_app_client(
	template_dir=str(pathlib.Path(__file__).parent / "test_templates")
	):

[simonw]

I've confirmed that it's the template_dir= line quoted above. It isn't the fault of pathlib - if you hard-code in the path string like this I still get the same failures:

    template_dir = "/Users/simonw/Dropbox/Development/datasette/tests/test_templates"
    for client in make_app_client(
        template_dir=template_dir
    ):

So for some reason setting template_dir to a concrete directory breaks those other tests.

[simonw]

Here's what isolated_filesystem() does:

A context manager that creates a temporary folder and changes the current working directory to it for isolated filesystem tests.

pallets/click#395 is a four year old issue suggesting allowing it to have a parent tmp directory passed to it, but since that issue was never closed I don't think it's going to help me.

[simonw]

This looks relevant: pytest-dev/pytest#1235 - "pytest explodes if getcwd fails"