Abstract: A downhole flow testing valve having a tubular housing with a valve and flow tube movable within the housing between an open position where valve ports therein are positioned in registry and a closed position where the valve ports are out of fluid communicating registry. The valve and flow tube is closed by a resultant force developed by compressed gas and opened by pressure introduced into the valve from the annulus between the valve and well casing. The normally closed flow testing shuttle valve is secured in its closed and safe condition during installation by a hydraulically locked sleeve valve. Upon fracture of a break plug by an implement dropped through the straight through flow passage of the flow tube hydraulic fluid captured within a locking chamber is released from the locking chamber by the force of a compression spring.