// The Base64-encoded user token is generated by the following command:
//     cat test_token.json | base64
// The Base64-encoded signature is generated by the following command:
//     cat test_token.json | openssl dgst -sha256 -binary -sign private.pem | base64
// The two are concatenated with a ':'.
// This token does not contain a "path" field, and therefore grants access to
// all Realms.

// Example:
g_signed_test_user_token =
 // cat test_token.json | base64
"ewogICJpZGVudGl0eSI6ICJ0ZXN0IiwKICAiYWNjZXNzIjogWwogICAgImRvd25sb2FkIiwKICAgICJ1cGxvYWQiCiAgXSwKICAidGltZXN0YW1wIjogMTQ1NTUzMDYxNCwKICAiZXhwaXJlcyI6IG51bGwsCiAgImFwcF9pZCI6ICJpby5yZWFsbS50ZXN0cy5zeW5jIgp9"
+ ":"
// cat test_token.json | openssl dgst -sha256 -binary -sign private.pem | base64
"Y5+K3Y+wd+McaZx6rte1MQvKpHgy7NoTqTzgF3CnGKcosMT7PkG1M71rLsq9/Fcldn6G26Bn3kb0vnw93TS2Ox4wa0FMiObK+N7VNdI6p/+dG5bDjBhtW2AFd2P0nOUCvx39EIdLVnGr3JUidJZEZGzFyFOdZVpnmIAnHNDaOIPOXt4vnASJ/dBjUTkOlexOwSRKIK1hvkA1GO9zpvnG5EbnVG6LuVSRM93Hp0tzuFdesns19P827/FsdZATDA9TFlwVTIa7vHz0KbzolSXKvIiOr5XWC2NXyDFEowxwFHyCuXN52jk9kylagFDTBvXu1ddmDZjWxg9SinJzS4lsYA=="


Reference https://github.com/realm/realm-sync/blob/master/test/test_sync.cpp#L65