procedures for revenue and receivables

Quite a few tests will help with both. For example, ensuring that no orders are lost, that invoices are issued for each despatch and that proper prices are used.

Whereas revenue accumulates during the year ie nearly all entries will be invoices ,net of sales tax, being credited to the sales acocunt, receivables are increased by the gross valus of invoices than reduced by cash received. Therefore you have to test that payments are being handled OK. You also have to assess the valuation of the receivables at year end.