package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	
	readInt := func() int {
		scanner.Scan()
		x := 0
		for _, b := range scanner.Bytes() {
			x = x*10 + int(b-'0')
		}
		return x
	}
	
	q := readInt()
	for ; q > 0; q-- {
		_ = readInt()
		n := readInt()
		p := make([]int, n)
		for i := 0; i < n; i++ {
			p[i] = readInt()
		}
		
		ans := 0
		for i := 0; i < n; {
			if i == n-1 {
				break
			}
			if p[i]-p[i+1] == 1 {
				next := 0
				if i+2 < n {
					next = p[i+2]
				}
				if p[i]-next > 2 {
					ans++
					i++
				} else {
					i += 2
				}
			} else {
				next := 0
				if i+2 < n {
					next = p[i+2]
				}
				if (p[i+1]+1)-next > 2 {
					ans++
					i++
				} else {
					i += 2
				}
			}
		}
		fmt.Println(ans)
	}
}