A solution using a CTE, if anyone should need that (apart from me, who obviously did, that is why I wrote it).
declare @StringToSplit varchar(100) = 'Test1,Test2,Test3';
declare @SplitChar varchar(10) = ',';
with StringToSplit as (
select
ltrim( rtrim( substring( @StringToSplit, 1, charindex( @SplitChar, @StringToSplit ) - 1 ) ) ) Head
, substring( @StringToSplit, charindex( @SplitChar, @StringToSplit ) + 1, len( @StringToSplit ) ) Tail
union all
select
ltrim( rtrim( substring( Tail, 1, charindex( @SplitChar, Tail ) - 1 ) ) ) Head
, substring( Tail, charindex( @SplitChar, Tail ) + 1, len( Tail ) ) Tail
from StringToSplit
where charindex( @SplitChar, Tail ) > 0
union all
select
ltrim( rtrim( Tail ) ) Head
, '' Tail
from StringToSplit
where charindex( @SplitChar, Tail ) = 0
and len( Tail ) > 0
)
select Head from StringToSplit