fix infinite recursion issue in test_f
fix infinite recursion issue in test_f

yukoba/sympy,wanglongqi/sympy,atreyv/sympy,oliverlee/sympy,jaimahajan1997/sympy,atsao72/sympy,farhaanbukhsh/sympy,AkademieOlympia/sympy,pandeyadarsh/sympy,farhaanbukhsh/sympy,rahuldan/sympy,Curious72/sympy,saurabhjn76/sympy,oliverlee/sympy,moble/sympy,atsao72/sympy,kaichogami/sympy,atreyv/sympy,ga7g08/sympy,asm666/sympy,debugger22/sympy,jbbskinny/sympy,meghana1995/sympy,Shaswat27/sympy,jerli/sympy,ChristinaZografou/sympy,skidzo/sympy,AkademieOlympia/sympy,maniteja123/sympy,rahuldan/sympy,Vishluck/sympy,kevalds51/sympy,madan96/sympy,sampadsaha5/sympy,VaibhavAgarwalVA/sympy,yukoba/sympy,sampadsaha5/sympy,Curious72/sympy,wanglongqi/sympy,ahhda/sympy,iamutkarshtiwari/sympy,postvakje/sympy,jbbskinny/sympy,jbbskinny/sympy,VaibhavAgarwalVA/sympy,garvitr/sympy,maniteja123/sympy,jaimahajan1997/sympy,lindsayad/sympy,pandeyadarsh/sympy,oliverlee/sympy,meghana1995/sympy,sahmed95/sympy,mafiya69/sympy,abhiii5459/sympy,jerli/sympy,aktech/sympy,grevutiu-gabriel/sympy,kevalds51/sympy,mafiya69/sympy,drufat/sympy,jaimahajan1997/sympy,souravsingh/sympy,ahhda/sympy,farhaanbukhsh/sympy,postvakje/sympy,Titan-C/sympy,chaffra/sympy,Designist/sympy,Vishluck/sympy,pbrady/sympy,ga7g08/sympy,wanglongqi/sympy,kumarkrishna/sympy,MechCoder/sympy,Arafatk/sympy,emon10005/sympy,hargup/sympy,yashsharan/sympy,debugger22/sympy,AkademieOlympia/sympy,yashsharan/sympy,debugger22/sympy,toolforger/sympy,abhiii5459/sympy,maniteja123/sympy,hargup/sympy,sahmed95/sympy,asm666/sympy,kevalds51/sympy,abloomston/sympy,shikil/sympy,lindsayad/sympy,Gadal/sympy,asm666/sympy,cswiercz/sympy,rahuldan/sympy,skidzo/sympy,grevutiu-gabriel/sympy,kaushik94/sympy,Titan-C/sympy,sahilshekhawat/sympy,wyom/sympy,kumarkrishna/sympy,toolforger/sympy,pandeyadarsh/sympy,sahilshekhawat/sympy,shikil/sympy,saurabhjn76/sympy,saurabhjn76/sympy,vipulroxx/sympy,atsao72/sympy,vipulroxx/sympy,drufat/sympy,kumarkrishna/sympy,cswiercz/sympy,chaffra/sympy,yashsharan/sympy,skidzo/sympy,garvitr/sympy,ChristinaZografou/sympy,jerli/sympy,chaffra/sympy,moble/sympy,kaushik94/sympy,bukzor/sympy,souravsingh/sympy,Gadal/sympy,drufat/sympy,grevutiu-gabriel/sympy,abloomston/sympy,ahhda/sympy,mafiya69/sympy,ga7g08/sympy,wyom/sympy,pbrady/sympy,sampadsaha5/sympy,MechCoder/sympy,souravsingh/sympy,Arafatk/sympy,abloomston/sympy,mcdaniel67/sympy,Davidjohnwilson/sympy,bukzor/sympy,sahilshekhawat/sympy,mcdaniel67/sympy,lindsayad/sympy,madan96/sympy,sahmed95/sympy,MechCoder/sympy,madan96/sympy,Curious72/sympy,abhiii5459/sympy,kaichogami/sympy,bukzor/sympy,Mitchkoens/sympy,aktech/sympy,toolforger/sympy,Designist/sympy,Titan-C/sympy,garvitr/sympy,moble/sympy,Davidjohnwilson/sympy,atreyv/sympy,kaichogami/sympy,kaushik94/sympy,wyom/sympy,postvakje/sympy,ChristinaZografou/sympy,Davidjohnwilson/sympy,vipulroxx/sympy,Mitchkoens/sympy,Mitchkoens/sympy,iamutkarshtiwari/sympy,Arafatk/sympy,aktech/sympy,hargup/sympy,Designist/sympy,emon10005/sympy,iamutkarshtiwari/sympy,meghana1995/sympy,cswiercz/sympy,VaibhavAgarwalVA/sympy,yukoba/sympy,shikil/sympy,mcdaniel67/sympy,pbrady/sympy,Vishluck/sympy,emon10005/sympy,Shaswat27/sympy,Gadal/sympy,Shaswat27/sympy