Can I get an unemployment benefit if I am forced to quit the job because I tested positive for Covid 19?

Forced to quit, yes.  Told you have to quarantine and have a negative test before you can come back to work, no.  That is covered under a sick leave policy and/or disability insurance and/or paid family leave.

Unemployment is for people who have been sacked through no fault of their own......... quitting means you deliberately made yourself unemployed and no one can force you to do that, you decided that

Usually you can get unemployment if you're forced to quit your job for any reason usually. 

That will depend on the state you live in. 

You were NOT "forced" to quit.

You chose to quit.

Unemployment is for those who were fired or laid off for no fault of their own AND are also available for work and seeking work.

If you're sick, youre not available for work

It depends on the specific State.  In some you CAN collect but there's a rather lengthy waiting period if you quit.

Are you in Ireland?  Austria?  India?

Laws differ around the world

You are never forced to quit a job.   By definition, if you quit you quit voluntarily and therefore are not eligible for unemployment.