#include <bits/stdc++.h>
#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3,"Ofast","inline")
#define hh "\n"
#define fi first
#define se second
#define inf 0x3f3f3f3f
#define mapa(a,b) make_pair(a,b)
#define tty template <typename T>
#define mm(a,b) memset(a,b, sizeof(a));
#define For(i,a,b) for(int i=a;i<=b;i++)
#define Rof(i,a,b) for(int i=a;i>=b;i--)
#define IOS ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
using namespace std;
typedef long long ll;
tty T gcd (T a, T b) {while (b ^= a ^= b ^= a %= b);  return a;}
inline char nc() {static char buf[1000000], *p1 = buf, *p2 = buf;return p1 == p2 && (p2 = (p1 = buf) + fread (buf, 1, 1000000, stdin), p1 == p2) ? EOF : *p1++;}
//#define nc getchar
tty inline void read(T &sum) {char ch = nc();T tf = 0;sum = 0;while((ch < '0' || ch > '9') && (ch != '-')) ch = nc();tf = ((ch == '-') && (ch = nc()));while(ch >= '0' && ch <= '9') sum = sum * 10+ (ch - 48), ch = nc();(tf) && (sum = -sum);}
tty inline void write(T x){char F[200];T tmp=x>0?x:-x ;if(x<0)putchar('-') ;T cnt=0 ;while(tmp>0){F[cnt++]=tmp%10+'0';tmp/=10;}while(cnt>0)putchar(F[--cnt]) ;}
tty inline void rmqmin(T f[][20],T n){for (int i = 1; i <= n; i++)cin >> f[i][0];for (int j = 1; j <= 20; j++)for (int i = 1; i <= n; i++)if (i + (1 << j) - 1 <= n)f[i][j] = min(f[i][j - 1], f[i + (1 << (j-1))][j - 1]);}
tty inline T zymin(T f[][20],T z,T y){int x=int (log(y-z+1)/log(2));return min(f[z][x],f[y-(1<<x)+1][x]);}
tty inline void rmqmax(T f[][20],T n){for (int i = 1; i <= n; i++)cin >> f[i][0];for (int j = 1; j <= 20; j++)for (int i = 1; i <= n; i++)if (i + (1 << j) - 1 <= n)f[i][j] = max(f[i][j - 1], f[i + (1 << (j-1))][j - 1]);}
tty inline T zymax(T f[][20],T z,T y){int x=int (log(y-z+1)/log(2));return max(f[z][x],f[y-(1<<x)+1][x]);}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

int a[100005];
void cf()
{
    int n,m,y,f=0,ff=0,fff=0,ffff=0;
    double ans=1,anss=1,v;
    cin>>n>>m;
    For(i,1,n)
    {
        cin>>a[i];
        if(a[i-1]>a[i])
            fff=1;
    }
    Rof(i,n,1)
    if(a[i]!=i)
    {
        f=i;
        break;
    }
    while (m--)
    {
        cin>>y>>v;
        if(y>=f)
        {
            ff=1;
            if(v==1)
            {
                ffff=1;
                cout<<"@1.000000\n";
                return;
            }
            ans*=(anss-v);
        }
    }
    if(fff==0||ffff==1)cout<<"1.000000\n";
    else if(ff==0) cout<<"0\n";
    else printf("%.10f\n",anss-ans);
}
int main()
{
    int t;
    cin>>t;
    while (t--) cf();
    return 0;
}