Go Testing

This teaches you to write Go tests the way Google and Uber do: table-driven tests with subtests, proper use of t.Error versus t.Fatal, and cmp.Diff for comparing complex types instead of assertion libraries. The normative guidance is opinionated but practical, like always printing "got" before "want" and never comparing error strings when you could check semantics with errors.Is. It includes a script to generate table test scaffolds and covers helpers, cleanup, and parallel execution. The "useful test failures" section nails something most guides skip: your error messages should be diagnosable without opening the source file.