Why it mattered
For some applications, the time the operating system kernel spends moving network data is the bottleneck. The vendor built network acceleration that bypasses the kernel, with its own API for sending and receiving data over TCP and UDP, for applications where low latency is the whole point.
A network stack only ships when it behaves correctly in thousands of situations nobody sees in a demo: every state of a TCP connection, every combination of socket options, every error path. Test coverage was what the release decision stood on.
How it works
- Test design from the API up. I analysed the tested API, designed the test API and the scenarios, and turned them into about 100 scenarios covering more than 1,500 test cases.
- A team of about five engineers on this project, within a team of up to seven that I led at the time: task planning, code review and training.
- The product was released on the strength of that coverage.
The same work continued into routing and containers, and the discipline carries straight into evaluating AI assistants.