An auditor discovered the following errors and irregularities while performing test of controls:

1. Goods received on June 3 were never placed in the storeroom but instead were taken to the receiving clerk's home.
2. Raw materials issued on July 15 were never recorded as issued from the storeroom.
3. Inventory damaged by a rain remains in inventory at full cost.
4. While the storeroom personnel are at lunch, production employees come into the storeroom to get the materials they need. They always complete and sign the requisition forms.
5. Sometimes the storeroom issues raw materials to production without obtaining a signature on a materials requisition.

REQUIRED:

a. What control should have prevented or detected which of the errors or irregularities?

b. What tests should the auditor perform to test each control?