Editing Code coverage (section)

{{Short description|Metric for source code testing}}
{{About|coverage based on source code|coverage based on requirements|Test coverage}}
{{Program execution}}

In [[software engineering]], '''code coverage''', also called '''test coverage''', is a percentage measure of the degree to which the [[source code]] of a [[computer program|program]] is executed when a particular [[test suite]] is run. A program with high code coverage has more of its source code executed during testing, which suggests it has a lower chance of containing undetected [[software bug]]s compared to a program with low code coverage.<ref name="Brader, 2013">{{cite book|last1=Brader|first1=Larry|last2=Hilliker|first2=Howie|last3=Wills|first3=Alan|title=Testing for Continuous Delivery with Visual Studio 2012|date=March 2, 2013|publisher=Microsoft|isbn=978-1621140184|page=30|url=https://msdn.microsoft.com/en-us/library/jj159344.aspx|access-date=16 June 2016|chapter=Chapter 2 Unit Testing: Testing the Inside}}</ref><ref name="Williams 2003">{{cite web|last1=Williams|first1=Laurie|author1-link=Laurie Williams (software engineer)|last2=Smith|first2=Ben|last3=Heckman|first3=Sarah|title=Test Coverage with EclEmma|url=http://realsearchgroup.org/SEMaterials/tutorials/eclemma|website=Open Seminar Software Engineering|publisher=North Carolina State University|access-date=16 June 2016|archive-url=https://web.archive.org/web/20160314023040/http://realsearchgroup.org/SEMaterials/tutorials/eclemma/|archive-date=14 March 2016|url-status=dead}}</ref> Many different metrics can be used to calculate test coverage. Some of the most basic are the percentage of program [[subroutine]]s and the percentage of program [[statement (computer science)|statements]] called during execution of the test suite.

Code coverage was among the first methods invented for systematic [[software testing]]. The first published reference was by Miller and Maloney in ''[[Communications of the ACM]]'', in 1963.<ref>{{cite journal
 | author       = Joan C. Miller, Clifford J. Maloney
 | title        = Systematic mistake analysis of digital computer programs
 | journal      = [[Communications of the ACM]]
 | volume       = 6
 | issue        = 2
 |date=February 1963
 | publisher    = [[Association for Computing Machinery|ACM]]
 | location     = New York, NY, USA
 | issn         = 0001-0782
 | pages        = 58–63
 | doi          = 10.1145/366246.366248
| doi-access= free
 }}</ref>