Fastify test suite had passing tests that could never fail, exposing a coverage blind spot

A developer discovered that several tests in the Fastify Node.js project contained assertions like `assert.ok(true)` that would pass regardless of whether the code under test actually worked. One test claimed to verify a server had started, but deleting the server logic entirely left the test green, since the only assertion was unconditionally true. The issue highlights a broader problem where code coverage metrics count executed lines without checking whether those lines would catch real regressions. The developer opened a pull request on the Fastify repository to replace the hollow assertions with meaningful checks, such as verifying the server is actively listening. To help teams detect similar issues, they also released a command-line scanner called `margyn-scan` that flags tests whose assertions can never fail.