Tests Hang and Fail when enabling a localhost tracing pipeline

[colemickens]

Hi.

I have recently modified our application to additionally send traces in Development/localhost mode. The Rust code notices its development and tries to construct a default-ish otlp pipeline. Those logs go to otel-collector, then Tempo, viewed in Grafana.

It's quite lovely, and I'm very happy about this otel ecosystem.

I am stumped with one issue -- when I run our tests, they seem to hang on anything that uses Axum. We execute our tests by constructing the Axum router (there-in creating the instrumentation layer), and then "executing"' requests against tit with call. I can't really think of any reason this wouldn't work.

For note, though I don't feel like a missing otel-collector should block anything, I also know that I'm running the otel-collector during tests. (The tests also need postgres, and I run otel-collector and postgres both in process-compose).