/*
#pragma GCC optimize("O2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2,fma")
//*/
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int  ,int > pii;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll maxn  = 3e6;
const ll mod =1e9+7;
const ld PI = acos((ld)-1);

#define pb push_back
#define endl '\n'
#define dokme(x) cout << x , exit(0)
#define migmig ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define ms(x , y) memset(x , y , sizeof x)
ll pw(ll a, ll b, ll md = mod){ll res = 1;while(b){if(b&1){res=(a*res)%md;}a=(a*a)%md;b>>=1;}return(res);}

int q;
int n , m;
int a[maxn];

ld p[maxn];
int r[maxn];

int32_t main(){
    migmig;
	cin >> q;
	while(q --){
		cin >> n >> m;
		for(int i = 1 ; i <= n ; i ++)
			cin >> a[i];
		for(int i = 1 ; i <= m ; i ++)
			cin >> r[i] >> p[i];
		int lst = -1;
		for(int i = n ; i ; i --){
			if(a[i] != i){
				lst = i;
				break;
			}
		}
		if(lst == -1){
			cout << 1 << endl;
			continue;
		}
		ld ans = 1;
		for(int i = 1 ; i <= m ; i ++){
			if(r[i] >= lst)ans*=(1 - p[i]);
		}
		cout << fixed << setprecision(10) << 1 - ans << endl;
	}



    return(0);
}
