As the title already says, it will not succeed:
name="{\"text\":\"Test\"}"and
name=Test will not find anything, even when summoning an entity with that exact value for CustomName, or a player with that name is online.
Linked issues
is duplicated by 6
MC-123775
Cannot execute from entity using "@e[name=<name>]"
Resolved
MC-123777
Commands cannot identify entity names properly
Resolved
MC-123851
Command Doens't work anymore
Resolved
MC-124026
The selector "name" does not work for players
Resolved
MC-124070
name selector isnt working
Resolved
1 more links
It seems like summoning entities also requires custom names to be JSON compliant, but this makes no sense, and additionally does not find entities by name at all.