Changes between Version 5 and Version 6 of Developer/Coverage/Theory
- Timestamp:
- 09/10/09 01:15:28 (15 years ago)
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Developer/Coverage/Theory
v5 v6 8 8 The subject of Code Coverage Analysis is broad and has been written about many times over. This background material is not intented to summerize or rehash what can be read elsewhere. Instead, the focus here will be on the aspects of Code Coverage Analysis as they pertain to the [wiki:TBR/UserManual/RTEMS_Coverage_Analysis RTEMS Coverage Analysis] effort. 9 9 10 The ultimate goal of Code Coverage Analysis is to ensure that every line of generated assembly in a particular configuration is executed by the test suite, that the tests exercise both taking and not taking every branch, and that every line of source code is actually tested. In order to achieve this goal, several different coverage criteria may have to be examined. Let's consider the following criteria:10 The ultimate goal of Code Coverage Analysis is to ensure that a test suite adequately tests a particular body of code. In order to achieve this goal, several different coverage criteria may have to be examined. Let's consider the following criteria: 11 11 12 12 * '''Object coverage''' - Has each line of generated assembly been executed? … … 16 16 * '''Modified Condition/Decision Coverage|Modified Condition/Decision Coverage (MC/DC)''' - Has every condition in a decision taken on all possible outcomes at least once? Has each condition been shown to affect that decision outcome independently? 17 17 18 Each of these criteria can be used independently to analyze the code in question. But there are clear relationships between the different criteria as shown in the picture. It is important 19 18 20 [[Image(CoverageCategories.png)]]]] 19 21 20 This is beyond statement level coverage in that we have to verify both paths of a C line like the following is executed: 22 If we consider the following example 21 23 22 24 {{{ 23 x = (y) ? z : a; 25 if (x || y) 26 do something 24 27 }}} 25 28 26 That is one statement but includes a branch. That makes it one point to cover when viewed using statement coverage. But it is two points to cover in our object level coverage of generated assembly. 29 and its psuedo object code 30 31 {{{ 32 cmp x, 0 33 branch if FALSE to do something 34 }}} 27 35 = Object Coverage = 28 36