Slices are Go's growable view over an array.

Key/value stores with the comma-ok lookup.

Composite types with attached methods and receivers.

Go composes types by embedding, not by inheritance.

Share and mutate with & and *.

Defer runs at function exit, in LIFO order.

Go strings are UTF-8 bytes; iterate with runes for characters.

Structural typing: implement the methods, satisfy the interface.

Errors are values you return, check, wrap, and inspect.

Extract a concrete type — and avoid the typed-nil trap.

Type parameters, added in Go 1.18.

Unrecoverable errors, and the escape hatch that stops them.

Prefix a call with `go` to run it concurrently.

Typed pipes that carry values between goroutines.

Wait on several channel operations at once.

Wait for goroutines to finish; guard shared state.

Guarantee one-time initialization across goroutines.

Encode and decode with struct tags.

net/http gives you a real server in a handful of lines.

Every project is a module tracked by go.mod.

Cancel, time out, and carry request-scoped values.

Files ending in _test.go and functions named TestXxx — exactly the harness you have been using.