case: [//alpha
node: [Text([//alpha)]
warn: [Warning(InvalidLinkSyntax)]

case: [//alpha beta\ngamma]
node: [Text([//alpha beta\ngamma])]
warn: [Warning(InvalidLinkSyntax)]

case: [//alpha beta]
node: [ExternalLink([Text(//alpha beta)])]
warn: []

case: [//alpha]
node: [ExternalLink([Text(//alpha)])]
warn: []

case: [//alpha] beta
node: [ExternalLink([Text(//alpha)]), Text( beta)]
warn: []

case: [//alpha]beta
node: [ExternalLink([Text(//alpha)]), Text(beta)]
warn: []

case: [HTTP://alpha]
node: [ExternalLink([Text(HTTP://alpha)])]
warn: []

case: [Http://alpha]
node: [ExternalLink([Text(Http://alpha)])]
warn: []

case: [alpha://beta]
node: [Text([alpha://beta])]
warn: []

case: [hTtP://alpha]
node: [ExternalLink([Text(hTtP://alpha)])]
warn: []

case: [http://alpha]
node: [ExternalLink([Text(http://alpha)])]
warn: []

case: [http:/alpha]
node: [Text([http:/alpha])]
warn: []

case: [http:alpha]
node: [Text([http:alpha])]
warn: []

case: [https://alpha]
node: [ExternalLink([Text(https://alpha)])]
warn: []

case: [sip:alpha]
node: [ExternalLink([Text(sip:alpha)])]
warn: []

case: alpha [//beta]
node: [Text(alpha ), ExternalLink([Text(//beta)])]
warn: []

case: alpha [//beta] gamma
node: [Text(alpha ), ExternalLink([Text(//beta)]), Text( gamma)]
warn: []

case: alpha[//beta]
node: [Text(alpha), ExternalLink([Text(//beta)])]
warn: []

case: alpha[//beta]gamma
node: [Text(alpha), ExternalLink([Text(//beta)]), Text(gamma)]
warn: []