test: add unit tests for Span-parsing helpers
test: add unit tests for Span-parsing helpers

tests the following four functions:
    - Const() [parse constant]
    - Func()  [parse function]
    - Expr()  [parse expression]
    - Split() [split up a string]

jambolo/bitcoin,gjhiggins/vcoincore,gjhiggins/vcoincore,yenliangl/bitcoin,namecoin/namecore,Xekyo/bitcoin,EthanHeilman/bitcoin,GroestlCoin/bitcoin,DigitalPandacoin/pandacoin,gjhiggins/vcoincore,prusnak/bitcoin,MarcoFalke/bitcoin,apoelstra/bitcoin,ajtowns/bitcoin,rnicoll/bitcoin,qtumproject/qtum,sipsorcery/bitcoin,anditto/bitcoin,ahmedbodi/vertcoin,litecoin-project/litecoin,instagibbs/bitcoin,particl/particl-core,prusnak/bitcoin,MeshCollider/bitcoin,jamesob/bitcoin,jnewbery/bitcoin,pstratem/bitcoin,JeremyRubin/bitcoin,yenliangl/bitcoin,tecnovert/particl-core,peercoin/peercoin,jonasschnelli/bitcoin,bitcoin/bitcoin,namecoin/namecoin-core,rnicoll/dogecoin,practicalswift/bitcoin,namecoin/namecore,rnicoll/dogecoin,pataquets/namecoin-core,sipsorcery/bitcoin,JeremyRubin/bitcoin,achow101/bitcoin,pstratem/bitcoin,jnewbery/bitcoin,jonasschnelli/bitcoin,litecoin-project/litecoin,ahmedbodi/vertcoin,peercoin/peercoin,rnicoll/bitcoin,bitcoinsSG/bitcoin,ajtowns/bitcoin,mitchellcash/bitcoin,apoelstra/bitcoin,tecnovert/particl-core,monacoinproject/monacoin,ElementsProject/elements,namecoin/namecore,sstone/bitcoin,bitcoinsSG/bitcoin,fanquake/bitcoin,sstone/bitcoin,instagibbs/bitcoin,kallewoof/bitcoin,vertcoin/vertcoin,andreaskern/bitcoin,mm-s/bitcoin,apoelstra/bitcoin,Sjors/bitcoin,vertcoin/vertcoin,tecnovert/particl-core,practicalswift/bitcoin,GroestlCoin/GroestlCoin,ajtowns/bitcoin,practicalswift/bitcoin,particl/particl-core,Sjors/bitcoin,Xekyo/bitcoin,JeremyRubin/bitcoin,bitcoin/bitcoin,prusnak/bitcoin,dscotese/bitcoin,prusnak/bitcoin,bitcoin/bitcoin,namecoin/namecoin-core,namecoin/namecore,pstratem/bitcoin,achow101/bitcoin,cdecker/bitcoin,bitcoinsSG/bitcoin,mm-s/bitcoin,MarcoFalke/bitcoin,alecalve/bitcoin,jambolo/bitcoin,instagibbs/bitcoin,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,kallewoof/bitcoin,fanquake/bitcoin,mruddy/bitcoin,jamesob/bitcoin,cdecker/bitcoin,practicalswift/bitcoin,sipsorcery/bitcoin,midnightmagic/bitcoin,tjps/bitcoin,rnicoll/bitcoin,monacoinproject/monacoin,peercoin/peercoin,apoelstra/bitcoin,cdecker/bitcoin,fanquake/bitcoin,mruddy/bitcoin,alecalve/bitcoin,n1bor/bitcoin,MarcoFalke/bitcoin,achow101/bitcoin,achow101/bitcoin,jamesob/bitcoin,tjps/bitcoin,DigitalPandacoin/pandacoin,bitcoinsSG/bitcoin,anditto/bitcoin,GroestlCoin/GroestlCoin,particl/particl-core,pstratem/bitcoin,dscotese/bitcoin,jlopp/statoshi,jnewbery/bitcoin,anditto/bitcoin,instagibbs/bitcoin,Sjors/bitcoin,pataquets/namecoin-core,rnicoll/dogecoin,domob1812/bitcoin,jamesob/bitcoin,bitcoinknots/bitcoin,sstone/bitcoin,ElementsProject/elements,jlopp/statoshi,andreaskern/bitcoin,namecoin/namecoin-core,MarcoFalke/bitcoin,fanquake/bitcoin,bitcoin/bitcoin,MeshCollider/bitcoin,pataquets/namecoin-core,mm-s/bitcoin,GroestlCoin/bitcoin,peercoin/peercoin,qtumproject/qtum,alecalve/bitcoin,jambolo/bitcoin,anditto/bitcoin,DigitalPandacoin/pandacoin,domob1812/namecore,ahmedbodi/vertcoin,cdecker/bitcoin,fujicoin/fujicoin,practicalswift/bitcoin,jlopp/statoshi,domob1812/bitcoin,Xekyo/bitcoin,domob1812/bitcoin,sipsorcery/bitcoin,n1bor/bitcoin,yenliangl/bitcoin,fujicoin/fujicoin,rnicoll/bitcoin,anditto/bitcoin,sipsorcery/bitcoin,rnicoll/bitcoin,lateminer/bitcoin,ajtowns/bitcoin,tecnovert/particl-core,andreaskern/bitcoin,JeremyRubin/bitcoin,AkioNak/bitcoin,bitcoinknots/bitcoin,alecalve/bitcoin,instagibbs/bitcoin,litecoin-project/litecoin,mitchellcash/bitcoin,pataquets/namecoin-core,qtumproject/qtum,mm-s/bitcoin,namecoin/namecoin-core,litecoin-project/litecoin,prusnak/bitcoin,yenliangl/bitcoin,yenliangl/bitcoin,fujicoin/fujicoin,domob1812/namecore,AkioNak/bitcoin,rnicoll/dogecoin,kallewoof/bitcoin,EthanHeilman/bitcoin,apoelstra/bitcoin,lateminer/bitcoin,Sjors/bitcoin,monacoinproject/monacoin,qtumproject/qtum,tjps/bitcoin,ahmedbodi/vertcoin,jnewbery/bitcoin,gjhiggins/vcoincore,fanquake/bitcoin,ElementsProject/elements,n1bor/bitcoin,pstratem/bitcoin,kallewoof/bitcoin,fujicoin/fujicoin,litecoin-project/litecoin,GroestlCoin/bitcoin,bitcoinsSG/bitcoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,bitcoinsSG/bitcoin,jambolo/bitcoin,bitcoinknots/bitcoin,pataquets/namecoin-core,monacoinproject/monacoin,tecnovert/particl-core,midnightmagic/bitcoin,EthanHeilman/bitcoin,dscotese/bitcoin,MarcoFalke/bitcoin,jlopp/statoshi,mitchellcash/bitcoin,prusnak/bitcoin,AkioNak/bitcoin,EthanHeilman/bitcoin,MarcoFalke/bitcoin,lateminer/bitcoin,monacoinproject/monacoin,tjps/bitcoin,mm-s/bitcoin,alecalve/bitcoin,apoelstra/bitcoin,cdecker/bitcoin,jonasschnelli/bitcoin,pataquets/namecoin-core,anditto/bitcoin,peercoin/peercoin,ajtowns/bitcoin,monacoinproject/monacoin,kallewoof/bitcoin,ElementsProject/elements,jambolo/bitcoin,achow101/bitcoin,pstratem/bitcoin,achow101/bitcoin,bitcoinknots/bitcoin,Sjors/bitcoin,AkioNak/bitcoin,EthanHeilman/bitcoin,MeshCollider/bitcoin,jamesob/bitcoin,mm-s/bitcoin,GroestlCoin/bitcoin,sstone/bitcoin,jamesob/bitcoin,MeshCollider/bitcoin,particl/particl-core,sipsorcery/bitcoin,yenliangl/bitcoin,domob1812/namecore,n1bor/bitcoin,gjhiggins/vcoincore,JeremyRubin/bitcoin,namecoin/namecoin-core,mruddy/bitcoin,MeshCollider/bitcoin,mitchellcash/bitcoin,mruddy/bitcoin,tjps/bitcoin,DigitalPandacoin/pandacoin,mitchellcash/bitcoin,GroestlCoin/bitcoin,Xekyo/bitcoin,Xekyo/bitcoin,particl/particl-core,bitcoin/bitcoin,dscotese/bitcoin,ElementsProject/elements,jlopp/statoshi,n1bor/bitcoin,midnightmagic/bitcoin,AkioNak/bitcoin,jonasschnelli/bitcoin,midnightmagic/bitcoin,andreaskern/bitcoin,GroestlCoin/bitcoin,namecoin/namecore,fujicoin/fujicoin,sstone/bitcoin,lateminer/bitcoin,vertcoin/vertcoin,practicalswift/bitcoin,vertcoin/vertcoin,AkioNak/bitcoin,mitchellcash/bitcoin,domob1812/bitcoin,rnicoll/bitcoin,GroestlCoin/GroestlCoin,n1bor/bitcoin,mruddy/bitcoin,lateminer/bitcoin,domob1812/namecore,domob1812/namecore,tecnovert/particl-core,jlopp/statoshi,fujicoin/fujicoin,domob1812/bitcoin,jambolo/bitcoin,fanquake/bitcoin,qtumproject/qtum,vertcoin/vertcoin,qtumproject/qtum,rnicoll/dogecoin,bitcoinknots/bitcoin,cdecker/bitcoin,lateminer/bitcoin,litecoin-project/litecoin,ahmedbodi/vertcoin,kallewoof/bitcoin,namecoin/namecore,MeshCollider/bitcoin,dscotese/bitcoin,dscotese/bitcoin,ajtowns/bitcoin,domob1812/namecore,namecoin/namecoin-core,alecalve/bitcoin,sstone/bitcoin,jnewbery/bitcoin,andreaskern/bitcoin,Xekyo/bitcoin,domob1812/bitcoin,ElementsProject/elements,EthanHeilman/bitcoin,midnightmagic/bitcoin,andreaskern/bitcoin,particl/particl-core,vertcoin/vertcoin,jonasschnelli/bitcoin,midnightmagic/bitcoin,mruddy/bitcoin,ahmedbodi/vertcoin,JeremyRubin/bitcoin,tjps/bitcoin,bitcoin/bitcoin,peercoin/peercoin,gjhiggins/vcoincore,qtumproject/qtum,instagibbs/bitcoin