String function to Find how many times str2 is in str1?

Good morning,

Is there a string function in PSQL to count how many times one str is in 
another string?

For example,
Str1 = "test   test   caa   dtest   testing   EndofString";
Str2 = "   ";

select funcName(Str1, Str2);

return 5

Because Str1 has 5 Str2.

Thanks !
Ly