Branch
A branch is a possible path of execution that results from a decision point in a program.
“A transfer of control between two consecutive nodes in the control flow graph of a test item.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Branch?
Branches occur whenever program logic can follow one of multiple paths, such as the true or false outcome of an if statement or a case within a switch statement.
Decision outcome: Every decision creates one or more branches that can be executed.
Testing significance: Branches are measured to evaluate how thoroughly decision logic has been tested.
Coverage relationship: Branches form the basis for branch coverage metrics.
Real World Example
A tax calculation module applies different deductions depending on income band, residency status, and submitted documents.
Reviewing the final tax amount is not enough when important code paths may never execute during testing. Branch helps the tester reason about the structure behind the result.
The tester works with the developer to identify decisions or paths in the calculation logic and designs inputs that exercise the meaningful alternatives.
The team gains better evidence about hidden logic because Branch connects tests to the implementation structure where certain defects can hide.
Practice Questions
Question 1
Which BEST defines a branch in white‑box testing?
Question 2
Which oversight MOST often hides branch defects?
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