De or het testopstelling?

The correct Dutch article is:

de testopstelling

Rule Words ending in -ing: almost always de. See the rule

How to use testopstelling

the testopstellingde testopstelling
this testopstellingdeze testopstelling
that testopstellingdie testopstelling
our testopstellingonze testopstelling
your testopstellingjouw testopstelling
every testopstellingelke testopstelling
which testopstelling?welke testopstelling?
a big testopstelling / the big testopstellingeen grote testopstelling, de grote testopstelling