extending
list1_ = 0x55e69a948080
list1->slab_ = 0x55e69a94c038
str1 = 0x55e69a948020
str2 = 0x55e69a948008
..  ints
-- before pop(0)
ints[0] = 4
ints[1] = 5
ints[2] = 6
-- after mutation
ints[0] = 42
ints[1] = 43
ints[2] = 6
list_repeat length = 3
list_repeat length = 3
item 0 1
item 1 1
.  forward iteration over list
x = 1
x = 2
x = 3
  backward iteration over list
x = 3
x = 2
x = 1
init.size() = 2
.-- before pop(0)
ints[0] = 5
ints[1] = 6
ints[2] = 7
ints[3] = 8
pop()
pop(0)
..  List<BigStr*>
  ints
......
Total: 12 tests (321 ticks, 0.000 sec), 131 assertions
Pass: 12, fail: 0, skip: 0.