In the first part of our series, we looked at QUERY, the first new HTTP method in 15 years. Today we’re talking about something you probably use every day without really understanding what you’re doing with it: caching headers.

In the first part of this series, we looked at Google Truth from the ground up - why it exists, how the subject model works, and when assertions become readable instead of cryptic.

You write a test. The test fails. You stare at the error message - and only after ten seconds do you understand what actually went wrong.