How to check if PHP rand() has randomly generated all the possible unique numbers by randomly generating numbers

I want to make sure that PHP rand() function has randomly generated all the possible unique numbers between the range given.

for example, this function rand(0,9) can generate unique numbers only 10 times right. ex: (randomly: 1,10,4,3,7,9,0,5,8,2,6)-(no duplication). So how do i determine that this rand() function has generated its all possible unique numbers?