Invalid Postgres's Schema Name

I’ve ‘Test’ schema in my Postgresql DB. Application correctly connects to it and I can do all of queries except CREATE which throws PDOException:

SQLSTATE[3F000]: Invalid schema name: 7 ERROR: schema "test" does not exist

And it’s right cause I’ve up cased first letter in my schema name.

What is it? A bug? Renaming to low case resolve this problem.