def visit(i, j):
    if grid[i][j] == '#':
        return 0
    grid[i][j] = '#'
    queue = [(i,j)]
    f = 0
    while f < len(queue):
        i, j = queue[f]; f += 1
        for di, dj in [(0,1),(1,0),(0,-1),(-1,0)]:
            ni,nj = i+di, j+dj
            if 0 <= ni < r and 0 <= nj < c:
                if grid[ni][nj] == 'o':
                    grid[ni][nj] = '#'
                    queue.append((ni,nj))
    return len(queue)

for cas in xrange(input()):
    r, c = map(int, raw_input().strip().split())
    grid = [list(raw_input()) for i in xrange(r)]
    g = float(visit(0, 0))
    ans = 1
    for i in xrange(r):
        for j in xrange(c):
            v = visit(i, j)
            ans += v / (v + g)
    print "%.11f" % ans