Some bugs only appear from a particular seat on the network. A service can be perfectly reachable from inside the lab and completely unreachable from a home device — or from the public internet — and a test that only checks one vantage point will happily call it green. Celilo’s end-to-end suite now makes assertions from multiple network perspectives, so “it works” has to mean “it works from where it actually needs to.”
Testing from where it matters
The end-to-end tests run against a simulated topology that mirrors a real deployment — separate networks for the different trust zones, a firewall between them, and vantage points that stand in for a home-LAN device, an internal server, and the outside internet. An assertion can be pinned to one of those vantages, so the suite can confirm that the same hostname resolves and connects correctly from each seat, not just from one convenient spot. When a fix depends on the network’s shape being right, the test proves it from the perspective that would break.
Assert the answer, not “it ran”
The point is to check the real outcome. A test asserts the specific address a client resolves, or that a connection from a given vantage actually succeeds — the things that silently differ between perspectives. That’s what catches the class of failure where a service looks healthy from the inside and is invisible from the outside, and it’s what keeps a fix from regressing the next time the network model changes.