A decision-to-decision path, or DD-Path, is a path of execution (usually through a graph representing a program, such as a flow-chart) that does not include any conditional nodes. That is, it is the path of execution between two decisions.
DD (decision-decision)' path is a path of nodes in a directed graph. A chain is a path in which:
A DD-path is a chain in a program graph such that:
It is a maximal chain of length ≥ 1.