Quart 0.20.0 test (`test_propagation`) breaks after Werkzeug update from 3.1.6 to 3.1.7

[ancieg]

Quart 0.20.0 test (test_propagation) breaks after Werkzeug update from 3.1.6 to 3.1.7.

To replicate the bug you just need to run testsuite:

$ python3 -m pytest -vra
        elif server is not None and server[1] is not None:
            host = server[0]

            # If SERVER_NAME is IPv6, wrap it in [] to match Host header.
            # Check for : because domain or IPv4 can't have that.
            if ":" in host and host[0] != "[":
                host = f"[{host}]"

            host = f"{host}:{server[1]}"
        else:
            host = ""

        if scheme in {"http", "ws"}:
            host = host.removesuffix(":80")
        elif scheme in {"https", "wss"}:
            host = host.removesuffix(":443")

        if not host_is_trusted(host, trusted_hosts):
>           raise SecurityError(f"Host {host!r} is not trusted.")
E           werkzeug.exceptions.SecurityError: 400 Bad Request: Host '' is not trusted.

/usr/lib/python3/site-packages/werkzeug/sansio/utils.py:141: SecurityError
=========================== short test summary info ============================
FAILED tests/test_app.py::test_propagation[True-False-True] - werkzeug.except...
FAILED tests/test_app.py::test_propagation[False-True-True] - werkzeug.except...
FAILED tests/test_app.py::test_propagation[True-True-True] - werkzeug.excepti...

Environment:

• Python version: 3.13.12
• Quart version: 0.20.0
• Werkzeug version: 3.1.7

See: pallets/werkzeug#3142

[Timnjr]

I encountered this issue in openSUSE Tumbleweed after the Werkzeug update. As a workaround I patched tests/conftest.py by changing "server": None to "server": ("localhost", 80) in both the http_scope and websocket_scope fixtures.
Note that this may resolve itself once Werkzeug 3.1.8 is released.