includes three tests
Change-Id: I33ac0cfe35085d4b6ad2775abcaa3d7d6527b49f
Reviewed-on: https://go-review.googlesource.com/c/go/+/297031
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>