Reverse proxies often are the key component in a web platform, be it eCommerce, B2B or anything else. Hence, they need to be rock solid. In my experience, reverse proxy outages only seldomly occur due to bugs in the proxy software itself, but rather from misconfiguration. You frequently have to modify reverse proxy configuration according to business needs. On each such change, you want to have a high degree of certainty that you don’t introduce regressions or security issues. After all, each such regression might result in degraded user experience or an outright outage of your site(s). In the context of microservices, integration testing is one of the building blocks for preventing regressions or undesired behavior. They are less often used for infrastructure components like reverse proxies. Nonetheless, they can be invaluable in preventing outages, which are often especially costly in reverse proxies.
In a past project, the customer utilized Prisma Cloud Compute for scanning running containers for known vulnerabilities (This is not endorsement of this particular software, just the one the customer decided to employ). In theory, it provided a detailed view of the container patch level within the organization. However, the end result was often one of two options: