fix(url): Fix WOKWI_CLI_SERVER being ignored

[lucasssvaz]

Problem

WokwiClient.__init__ falls back to the hard-coded public URL when server is not given:

self._transport = Transport(token, server or DEFAULT_WS_URL)

Because the client always passes a URL, the default in transport.py (TRANSPORT_DEFAULT_WS_URL = os.getenv("WOKWI_CLI_SERVER", DEFAULT_WS_URL)) is never used. As a result, WOKWI_CLI_SERVER is silently ignored by both WokwiClient and WokwiClientSync unless server is passed explicitly.

In practice this affects anyone using wokwi/wokwi-ci-server-action. The action sets WOKWI_CLI_SERVER=ws://localhost:9177, but clients created with just a token, such as the one in pytest-embedded-wokwi, still connect to wss://wokwi.com/api/ws/beta. The self-hosted CI server is bypassed and all simulations go to the shared public endpoint. In espressif/arduino-esp32 we've been seeing more and more intermittent ConnectionClosedError: no close frame received or sent and HTTP 503 failures because of this.

Fix

Fall back to TRANSPORT_DEFAULT_WS_URL instead of DEFAULT_WS_URL, so the existing environment variable lookup in transport.py is respected. An explicit server argument still takes priority.

Tests

Added tests/test_server_url.py, which runs without a token or network access and covers:

• no server and no WOKWI_CLI_SERVER: uses the public server
• no server with WOKWI_CLI_SERVER set: uses the environment variable
• explicit server with WOKWI_CLI_SERVER set: uses the explicit server

Each case runs in a subprocess, because WOKWI_CLI_SERVER is read when wokwi_client.transport is imported.

[urish]

Thanks!

[urish]

Fixed released as v0.4.1