fix test coverage on multibackend deprecated methods
fix test coverage on multibackend deprecated methods

skeuomorf/cryptography,sholsapp/cryptography,Ayrx/cryptography,bwhmather/cryptography,skeuomorf/cryptography,dstufft/cryptography,dstufft/cryptography,kimvais/cryptography,Ayrx/cryptography,kimvais/cryptography,Hasimir/cryptography,skeuomorf/cryptography,Hasimir/cryptography,Hasimir/cryptography,kimvais/cryptography,kimvais/cryptography,sholsapp/cryptography,dstufft/cryptography,Ayrx/cryptography,skeuomorf/cryptography,sholsapp/cryptography,Hasimir/cryptography,bwhmather/cryptography,bwhmather/cryptography,sholsapp/cryptography,dstufft/cryptography,Ayrx/cryptography,bwhmather/cryptography,dstufft/cryptography