package main

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

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	
	nextInt := func() int {
		scanner.Scan()
		res, _ := strconv.Atoi(scanner.Text())
		return res
	}
	
	nextFloat := func() float64 {
		scanner.Scan()
		res, _ := strconv.ParseFloat(scanner.Text(), 64)
		return res
	}

	if !scanner.Scan() {
		return
	}
	t, _ := strconv.Atoi(scanner.Text())
	
	for i := 0; i < t; i++ {
		n := nextInt()
		m := nextInt()
		
		pos := 0
		for j := 1; j <= n; j++ {
			val := nextInt()
			if val != j {
				pos = j
			}
		}
		
		failProb := 1.0
		for j := 0; j < m; j++ {
			r := nextInt()
			p := nextFloat()
			if r >= pos {
				failProb *= (1.0 - p)
			}
		}
		
		if pos == 0 {
			fmt.Printf("%.6f\n", 1.0)
		} else {
			fmt.Printf("%.6f\n", 1.0 - failProb)
		}
	}
}