Improve assert message
Improve assert message

nojvek/TypeScript,nojvek/TypeScript,SaschaNaz/TypeScript,RyanCavanaugh/TypeScript,alexeagle/TypeScript,donaldpipowitch/TypeScript,SaschaNaz/TypeScript,nojvek/TypeScript,Microsoft/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,alexeagle/TypeScript,donaldpipowitch/TypeScript,kitsonk/TypeScript,minestarks/TypeScript,microsoft/TypeScript,RyanCavanaugh/TypeScript,basarat/TypeScript,weswigham/TypeScript,weswigham/TypeScript,Microsoft/TypeScript,kitsonk/TypeScript,RyanCavanaugh/TypeScript,weswigham/TypeScript,SaschaNaz/TypeScript,kitsonk/TypeScript,minestarks/TypeScript,SaschaNaz/TypeScript,basarat/TypeScript,minestarks/TypeScript,basarat/TypeScript,kpreisser/TypeScript,nojvek/TypeScript,alexeagle/TypeScript,donaldpipowitch/TypeScript,kpreisser/TypeScript,microsoft/TypeScript,donaldpipowitch/TypeScript,basarat/TypeScript,kpreisser/TypeScript