[WIP] Test into

Changed one function around. Wasnt working before, fixed it, added chunksize argument. Not sure if we want this to be a pattern, where we add chunksize arguments for functions which use chunks.

Also the code looks ugly and can probably be done better. 
get all these values out, then close the file, then do the assertions. windows will complain about the file not being closed if you don't do this.

something like this:

```python
ctn = len(ct)
tn = len(tble)
ctf, ctl = ct[0], ct[-1]
tbf, tbl = tble[0], tble[-1]
tble._v_file.close()
assert ctn == tbn
assert ctf == tbf
assert ctl == tbl
```