function compareEntries( actual, expected ) {
	var i;
	if ( actual.length !== expected.length ) {
		return 'Expected entries ['+expected+'], but observed ['+actual+']';
	}
	for ( i = 0; i < expected.length; i++ ) {
		if ( !checkPrimitive( actual[ i ], String( expected[ i ] ) ) ) {
			return 'Expected entries ['+expected+'], but observed ['+actual+']';
		}
	}
	return null;
}
Compares a list of expected entries with a list of actual values.

@private
@param {Collection} actual - list of actual values
@param {Collection} expected - list of expected values
@returns {(string|null)} result