The previous tests/server/conftest.py called trace.set_tracer_provider()
directly, which is set-once per process and raced against logfire's capfire
fixture (tests/shared/test_otel.py) under xdist — whichever ran first in a
worker won, the other's tests broke.
Converge on capfire as the single span-capture owner since logfire.configure()
already handles repeat calls by swapping span processors instead of re-setting
the provider:
- tests/conftest.py: set LOGFIRE_DISTRIBUTED_TRACING=true so propagation tests
don't trip logfire's 'found propagated trace context' RuntimeWarning.
- tests/server/conftest.py: SpanCapture adapter over capfire.exporter — filters
to the mcp-python-sdk instrumentation scope and excludes logfire's
pending_span markers, so tests assert on raw ReadableSpan without importing
logfire types.
- tests/shared/test_otel.py: drop the now-unneeded filterwarnings decorator.
Max Isbey
918e20aba0