The auditor has documented the following internal control procedures designed and implemented by Sunflower Trading Berhad for the purchasing business process:

1. All requests for purchases must complete the purchase requisition form and approved by the respective requesting department before submitting the form to the purchasing clerk. The purchasing clerk will then prepare a pre-numbered purchase order to suppliers. The purchasing clerk attach the approved purchase requisition form to the purchase order. The purchasing manager signs on the purchase order as evidence of approval.
2. The purchasing department, accounting department, receiving department and shipping department are independent of each other, with different roles and responsibilities.
3. A monthly report summarising budgeted expenditure to actual expenditure is required to be prepared by all departmental managers, who also signed on the report. Unexpected variances are investigated and explained in the monthly report.
4. A responsible officer shall sign on the purchase invoices. The purchase invoice is attached to be payment voucher which is signed by the accountant, before payments are made.
5. The purchasing manager reviews and investigates any unmatched receiving reports, and signs on the monthly review report as evidence of the review.

Required:

For each of the internal controls described in the case above, explain the audit test that should be performed by the auditors to determine the effectiveness of the controls.