//	}
//
// If the file is in a separate "_test" package, the package being tested
// must be imported explicitly and only its exported identifiers may be used.
// This is known as "black box" testing.
//
//	package abs_test
//
//	import (
//		"testing"
//
//		"path_to_pkg/abs"
//	)
//
//	func TestAbs(t *testing.T) {
//	    got := abs.Abs(-1)
//	    if got != 1 {
//	        t.Errorf("Abs(-1) = %d; want 1", got)