assert = function(arg) {
          switch (arg.constructor) {
            case RegExp   : return arg.test(e.message || e.toString())
            case String   : return arg == (e.message || e.toString())
            case Function : return e instanceof arg || e.name == arg.name
          }
        }
Load, pre-process, and evaluate a file.

@param {string} file
@param {JSpec}
@api public