Testing in Production

 Once I believed that no "real" testing should be done in production as it is "real" environment that customers use and no "tinkering around" that.

Of late I have seen many cases where doing prod sanity (what a phrase) has become necessary. Whenever a bug escapes to production - first question asked is "was it noticed in staging or QA" - if the answer is "no' - enter "testing in production".

For various reasons - QA/Staging happens to be different from production. While one can understand and appreciate these differences from data/system config point of view --- in terms of code and related software config?

Testers work hard and sign off on stage/QA environment thinking that same "code and config" will be promoted or replicated to production. When this expectation breaks - bugs escape to production.

This is an "avoidable" mistake ... please watchout