I currently work as a Software tester for a leading wall street foreign exchange trading firm.

Salam waalaiykum, I would like to enquire if my income is halal or not. I currently work as a Software tester for a leading wall street foreign exchange trading firm.
My basic function is to test the Back Office software. This software performs all calculations, account setups, and configurations, as well as facilitates the Trading in foreigne xchange.
My confusions stems from the fact that it is through this software that the interest that customers pay, earn, and the firm itself pays and earns is calculated. Also, in foreign exchange trading there is a high level of speculation.
Our custoemrs do have the option to trade on 0 interst and pay commission. This facility has been introduced by the firm for our muslim clientele.
However, when testing I have to make sure that the software works for all setups.

Am I then in any way part of the interest based transaction, and/or am I in any way as a tester - testing in the TEST environment only - facilitating the haram interest based transactions in any way?
Or am I external to the trades, since I am only part of testing to make sure that the Programmers correctly implement the requirements laid down by business.
I get a document that lists the requirements, and I test to make sure that they have been correctly implemented, and that the system works.