nim-stew/tests/ranges/tstackarrays.nim

49 lines
1.2 KiB
Nim

import
unittest, math,
../../stew/ptrops,
../../stew/ranges/[stackarrays]
suite "Stack arrays":
test "Basic operations work as expected":
var arr = allocStackArray(int, 10)
check:
type(arr[0]) is int
arr.len == 10
# all items should be initially zero
for i in arr: check i == 0
for i in 0 .. arr.high: check arr[i] == 0
arr[0] = 3
arr[5] = 10
arr[9] = 6
check:
sum(arr.toOpenArray) == 19
arr[5] == 10
arr[^1] == 6
cast[ptr int](offset(addr arr[0], 5))[] == 10
test "Allocating with a negative size throws a RangeError":
expect RangeError:
discard allocStackArray(string, -1)
test "The array access is bounds-checked":
var arr = allocStackArray(string, 3)
arr[2] = "test"
check arr[2] == "test"
expect RangeError:
arr[3] = "another test"
test "proof of stack allocation":
proc fun() =
# NOTE: has to be inside a proc otherwise x1 not allocated on stack.
var x1 = 0
var arr = allocStackArray(int, 3)
check:
# stack can go either up or down, hence `abs`.
# 1024 should be large enough (was 312 on OSX).
abs(cast[int](x1.addr) - cast[int](addr(arr[0]))) < 1024
fun()