nl_tokens: Returns a string of expected arguments vs actual .
pl_tokens: function ( expected , actual ) { var argNames = [ ] ; var expectedNames = [ ] ; for ( var i = 0 ; i < actual . length ; i ++ ) { argNames . push ( getNameForValue ( actual [ i ] ) ) ; } ; for ( var i = 0 ; i < expected . length ; i ++ ) { expectedNames . <mask> ( getNameForType ( expected [ i ] ) ) ; } ; return 'Expected arguments to be (' + expectedNames . join ( ', ' ) + ') but received (' + argNames . join ( ', ' ) + ') instead.' ; }