Software error costs Boeing Starliner program $410M in 2020

From the article: "Boeing did not perform an end-to-end test of the entire software suite"

I once worked with a guy who did a solo piece of work and after 3 months of effort declared it done. My boss asked me to test it. In 10 minutes, my test of its one and only basic function failed. My boss turned to the guy and said "Did you test this?". He said "All my unit tests passed".

Unit tests don't tell you anything about overall functionality. Somehow, too many people don't know this simple fact.