// runs multiple packages, again use "go test -json".
//
// # Output Format
//
// The JSON stream is a newline-separated sequence of TestEvent objects
// corresponding to the Go struct:
//
//	type TestEvent struct {
//		Time    time.Time // encodes as an RFC3339-format string
//		Action  string
//		Package string
//		Test    string
//		Elapsed float64 // seconds
//		Output  string