output

$ go run score.go 
Test: [1 2 3]
	score=0
Test: [2 1 3]
	score=1
Test: [3 2 1]
	score=2
Test: [1 2 4 3 5]
	score=1
Test: [1 2 4 3 5 6 8 9 7]
	score=2

score.go

package main

import "fmt"

func sortScore(a []int) int {
	var score int

	for i := 0; i < len(a)-1; i++ {
		if a[i] > a[i+1] {
			score++
		}
	}
	return score
}

func main() {
	tests := [][]int{
		[]int{1, 2, 3},
		[]int{2, 1, 3},
		[]int{3, 2, 1},
		[]int{1, 2, 4, 3, 5},
		[]int{1, 2, 4, 3, 5, 6, 8, 9, 7},
	}

	for _, t := range tests {
		fmt.Println("Test:", t)
		fmt.Printf("\tscore=%d\n", sortScore(t))
	}
}