codeforces-b

from sys import stdin, stdout
import math
R = lambda : stdin.readline().strip()
RL = lambda f=None: list(map(f, R().split(' '))) if f else list(R().split(' '))

output = lambda x: stdout.write(str(x) + '\n')
output_list = lambda x: output(' '.join(map(str, x)))

for tc in range(int(R())):
    n = int(R())
    a = RL(int)
    val = [0]
    intm = 0
    for i in range(1, n-1):
        if a[i-1] > a[i] < a[i+1]:
            val.append(-1)
            intm += 1
        elif a[i-1] < a[i] > a[i+1]:
            val.append(1)
            intm += 1
        else:
            val.append(0)
    val.append(0)
    ans = intm
    for i in range(1,n-1):
        if (val[i] == -1 and val[i-1] == 1 and val[i+1] ==1) or (val[i] == 1 and val[i-1] == -1 and val[i+1] ==-1):
            ans = min(ans, intm-3)
        elif (val[i] == -1 and [0,1] == sorted([val[i-1], val[i+1]])) or (val[i] == 1 and [-1,0] == sorted([val[i-1], val[i+1]])):
            ans = min(ans, intm -2)
        else:
            ans = min(ans, intm-1)
    output(max(0, ans))