Decision-to-decision path

In Huang's 1975 paper,{{cite journal|last=Huang|first=J.C.|title=An Approach to Program Testing|journal=Computing Surveys|date=September 1975|volume=7|issue=3|pages=118–119|doi=10.1145/356651.356652}}

The definition given there is citing: "Fortran automated verification system Level 1 — user's guide, Program Validation Project, General Research Corp., October 1974." a decision-to-decision path is defined as path in a program's flowchart such that all the following hold (quoting from the paper):

• its first constituent edge emanates either from an entry node or a decision box;
• its last constituent edge terminates either at a decision box or at an exit node; and
• there are no decision boxes on the path except those at both ends

Jorgensen's more recent textbooks restate it in terms of a program's flow graph (called a "program graph" in that textbook). First define some preliminary notions: chain and a maximal chain. A chain is defined as a path in which:

• initial and terminal nodes are distinct, and
• all interior nodes have in-degree = 1 and out-degree = 1.

A maximal chain is a chain that is not part of a bigger chain.

A DD-path is a set of nodes in a program graph such that one of the following holds (quoting and keeping Jorgensen's numbering, with comments added in parentheses):

1. It consists of a single node with in-degree = 0 (initial node)
2. It consists of a single node with out-degree = 0 (terminal node)
3. It consists of a single node with in-degree ≥ 2 or out-degree ≥ 2 (decision/merge points)
4. It consists of a single node with in-degree = 1 and out-degree = 1
5. It is a maximal chain of length ≥ 1.

According to Jorgensen (2013), in Great Britain and ISTQB literature, the same notion is called linear code sequence and jump (LCSAJ).{{dubious|date=July 2014}}

From the latter definition (of Jorgensen) we can conclude the following:

• Every node on a flow graph of a program belongs to one DD-path.
• If the first node on a DD-path is traversed, then all other nodes on that path will also be traversed.
• The DD path graph is used to find independent path for testing.
• Every statement in the program has been executed at least once.

According to Jorgensen's 2013 textbook, DD-path testing is the best known code-based testing method, incorporated in numerous commercial tools.{{cite book|author=Paul C. Jorgensen|title=Software Testing: A Craftsman's Approach, Fourth Edition|year=2013|publisher=CRC Press|isbn=978-1-4665-6068-0|pages=136–137}}

DD-path testing is also called C2 testing or branch coverage.{{cite book|author1=Judith A. Clapp|author2=Saul F. Stanten|author3=W.W. Peng |author4=D.R. Wallace |author5=Deborah A. Cerino |author6=Roger J. Dziegiel Jr. |title=Software Quality Control, Error, Analysis|year=1995|publisher=William Andrew|isbn=978-1-4377-4484-2|pages=347–348}}{{cite book|author=J. C. Huang|title=Software Error Detection through Testing and Analysis|url=https://archive.org/details/softwareerrordet00huan|url-access=limited|year=2009|publisher=John Wiley & Sons|isbn=978-0-470-46405-2|pages=[https://archive.org/details/softwareerrordet00huan/page/n175 164]–165}}

• Basic block
• Basis path testing and its ancillary articles
• Cyclomatic complexity
• Essential complexity
• Code coverage
• White-box testing

{{Reflist}}

• http://www.eecs.yorku.ca/course_archive/2011-12/W/4313/slides/11-Paths.pdf

Category:Software testing

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