Tests

**As a** store owner,
    **I want** to add items back to inventory when they are returned or exchanged,
        **so that** I can track inventory.

**Scenario 1**: Items returned for refund should be added to inventory.
    **Given** that a customer previously bought a black sweater from me
    **and** I have three black sweaters in inventory,
    **when** they return the black sweater for a refund,
    **then** I should have four black sweaters in inventory.

**Scenario 2**: Exchanged items should be returned to inventory.
    **Given** that a customer previously bought a blue garment from me
    **and** I have two blue garments in inventory
    **and** three black garments in inventory,
    **when** they exchange the blue garment for a black garment,
    **then** I should have three blue garments in inventory
    **and** two black garments in inventory.