jupyter: additional key:value store tests on backend
jupyter: additional key:value store tests on backend

DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc