Oil tankers are beginning to test the waters at the Strait of Hormuz. At least eight crude carriers started advancing toward the chokepoint within hours of Iran declaring the Strait open to shipping under a ceasefire framework. Five vessels that had been idling north of Dubai moved first, followed by three more positioned roughly 70 miles west, according to vessel tracking data cited by Bloomberg. It’s the first real sign of life in a corridor that has effectively been frozen since late February, when conflict in the region choked off flows…