#include <bits/stdc++.h>
#define PI atan(1.0)*4
#define rp(i,s,t) for (register int i = (s); i <= (t); i++)
#define RP(i,t,s) for (register int i = (t); i >= (s); i--)
#define sc(x) scanf("%d",&x)
#define scl(x) scanf("%lld",&x)
#define ll long long
#define ull unsigned long long
#define mst(a,b) memset(a,b,sizeof(a))
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pil pair<int,ll>
#define m_p make_pair
#define p_b push_back
#define ins insert
#define era erase
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define dg if(debug)
#define outval(a) cout << "Debuging...|" << #a << ": " << a << "\n";
using namespace std;
int debug = 0;
ll gcd(ll a,ll b){
	return b?gcd(b,a%b):a;
}
ll lcm(ll a,ll b){
	return a/gcd(a,b)*b;
}
inline int read(){
	int s=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		s=s*10+ch-'0';
		ch=getchar();
	}
	return s*f;
}
const int N = 1e6+7;
const double eps = 1e-7;
int a[N];
int f[N];
void solve(){
	int n=read(),m=read();
	rp(i,1,n) a[i]=read();
	rp(i,1,n) f[i]=0;
	RP(i,n,1){
		if(a[i]!=i) break;
		else f[i]=1;
	}
	int flag=1;
	rp(i,1,n){
		if(f[i]==0){
			flag=0;
		}
	}
	double ans=0.0;
	double cur=1;
	int ff=0;
	rp(i,1,m){
		int r;double p;
		scanf("%d%lf",&r,&p);
		// printf("%d %lf\n",r,p);
		if(r==n||f[r+1]){
			ans+=cur*p;
			cur*=(1.0-p);
			if(fabs(p-1.0)<=eps) ff=1;
		}
	}
	if(ff||flag){
		printf("1.000000\n");
		return ;
	}
	printf("%.6f\n",ans);
}
int main(){
	//ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#ifdef ONLINE_JUDGE
#else
	freopen("in.txt", "r", stdin);
	//debug = 1;
#endif
	time_t beg, end;
	//if(debug) beg = clock();

	int T=read();
	while(T--) solve();

	/*
	if(debug) {
		end = clock();
		printf("time:%.2fs\n", 1.0 * (end - beg) / CLOCKS_PER_SEC);
	}
	*/
	return 0;
}