Francis pointed out in review of #7669 that the echo handler — which
exists solely as a test upstream for the WebTransport reverse-proxy
tests — should not be a full-fledged module registered in every Caddy
binary. Mirroring the mockdns_test.go pattern, move it into a _test.go
file under caddytest/integration/.
The module ID http.handlers.webtransport is now registered only when
the integration test binary is built, which is when
caddytest/integration/webtransport_test.go references it by ID string
in its JSON configs. Production Caddy builds no longer include it.
Changes:
* New file: caddytest/integration/webtransport_echo_test.go —
contains the WebTransportEcho handler, its types and interface
guards, the isWebTransportEchoUpgrade helper, and the unit tests
that used to live in the deleted package's handler_test.go.
* Deleted: modules/caddyhttp/webtransport/ (handler.go + handler_test.go).
* Removed the blank import from modules/caddyhttp/standard/imports.go.
The Protocol const and Writer interface that this package used to
export were inlined into reverseproxy's own files in a preceding
commit, so nothing else depends on the deleted package.
8d86214d1c