Decision Coverage Testing in White Box Testing

Posted on: October 3rd, 2022 by Cathy Caldwell No Comments

On the other hand, in condition coverage, all possible outcomes of all conditions must be tested at least once. Condition coverage testing is a type of white-box testing that tests all the conditional expressions in a program for all possible outcomes of the conditions. However, this kind of “cheating” can be done to simplify expressions, not simply to avoid MC/DC complexities. For example, assignment of the number of days in a month could be achieved by using either a switch statement or by using a table with an enumeration value as an index.

Some code coverage tools do not use this strict interpretation of a decision and may produce false positives (reporting 100% code coverage when indeed this is not the case). Condition Coverage or expression coverage is a testing method used to test and evaluate the variables or sub-expressions in the conditional statement. The goal of condition coverage is to check individual outcomes for each logical condition. Condition coverage offers better sensitivity to the control flow than decision coverage. In this coverage, expressions with logical operands are only considered. In computer science, code coverage is a percentage measure of the degree to which the source code of a program is executed when a particular test suite is run.

Result :

Each individual condition must be shown to alter the result independently. It plays a role as a supporting agent for keeping in check that there are no unfinished or obsolete pieces of code or functionalities left unnoticed in the application. Where the total number of decisions will be the count of the logical decisions identified in the program and the number of decisions implemented out of them will give the Decision Coverage percentage value. Decisions are recursive in that a decision can contain decisions as in the last example above. The decision X || C is one decision and X is actually another decision (A && B).A, B and C are conditions, because they contain no Boolean operators. A Condition is a Boolean expression containing no Boolean operators.

  • As one might expect, there are classes of software that cannot be feasibly subjected to these coverage tests, though a degree of coverage mapping can be approximated through analysis rather than direct testing.
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  • In this case, the three assignments should be treated as a decision for MC/DC purposes and therefore the changed code needs exactly the same tests and number of tests to achieve MC/DC than the first one.
  • Software authors can look at test coverage results to devise additional tests and input or configuration sets to increase the coverage over vital functions.
  • The last and final step in the Decision Coverage testing process is to evaluate logical decision indications gathered and designed in the previous steps of this testing process.
  • It also checks how many sequences are included in a finite state machine.
  • And, if the condition is met and found to be true, then the patient can be marked as a senior citizen.

However, this set of tests does not satisfy branch coverage since neither case will meet the if condition. To measure what percentage of code has been executed by a test suite, one or more coverage criteria are used. These are usually defined as rules or requirements, which a test suite must satisfy.

Software Testing

If the match is faultless, then the message ‘ is the correct answer’ will be displayed. If the results are unmatched, then the message ‘Your answer is wrong’ will be displayed. Hence this code consists of two possible logical decisions, and testing the scope of this code can be called as the Decision Coverage Testing. There is a relation between the two sources, but there are differences. Branch Coverage technique involves checking whether every possible path or branch is covered. Branching is actually a jump from one decision point to another.

decision condition coverage testing

The proceeding steps involve the process of assembling a logical decision making flowchart and to list the results or outcomes of the various decisions instilled in the application’s code. It can most likely have more than one conclusion, as one consistent code execution flow doesn’t need to involve any logical decision to be made. To calculate Branch Coverage, one has to find out the minimum number of paths which will ensure that all the edges are covered. In this case there is no single path which will ensure coverage of all the edges at once. It helps in validating all the branches in the code making sure that no branch leads to abnormal behavior of the application. Condition coverage reports the true or false outcome of each condition.

Test Coverage vs Code Coverage

The above pseudocode checks the if condition, if it evaluates to be true, the next statement should execute else the print statement inside else. Ideally this flow is normal, if there is any deviation in this, that must be identified using test cases. Here it is relevant to vary in the outcome of the decision, and in the outcomes of the conditions. Since there are only two possible outcomes of a decision , and there are only two outcomes of a conditon, test situations can be created in such a way that only 2 test situations per decision point are needed.

Software authors can look at test coverage results to devise additional tests and input or configuration sets to increase the coverage over vital functions. Two common forms of test coverage are statement coverage and branch coverage. Line coverage reports on the execution footprint of testing in terms of which lines of code were executed to complete the test. Edge coverage reports which branches or code decision points were executed to complete the test. The meaning of this depends on what form of coverage have been used, as 67% branch coverage is more comprehensive than 67% statement coverage.

Examples to Implement of Decision Coverage

The process of performing this evaluation in terms of the modular functionality, without any leakage, can be defined as the practice of the Decision Coverage validation. Therefore coverage techniques are a great way to analyse and present the functioning of program in the light of specifications. This technique aims to cover the various conditions and its consecutive flow. A condition or predicate when evaluates to true must execute the next relevant line of code that follows. However if the categorization leads to an unnecessary reduction of options for the tester, then we should cease using those categories. Second, the number of tests should be relative to the complexity of the code.

A Decision is a Boolean expression composed of conditions and zero or more Boolean operators. If a condition appears more than once in a decision, each occurrence is a distinct condition. CDC ensures that all conditions and decisions are working fine or not. TMAP is Sogeti’s body of knowledge for quality engineering and testing in IT delivery and builds on practical experience from thousands of people since 1995, keeping up with changing businesses and technology.

What is Modified Condition/Decision Coverage?

This can be done by manually running the tests and counting the number of lines that are executed, or by using a tool that automatically instruments the code and tracks which lines are executed. Scenario to calculate Statement Coverage for given source code. Here we are taking two different scenarios to check the percentage of statement coverage for each scenario. There are also some sorts of defects which are affected by such tools. Test 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.

decision condition coverage testing

Both beginner level and expert level PHP Certification Exams are offered by StudySection along with other programming certification exams. Specifications are frequently used as a secondary data source when determining the expected outcome of test cases. Test numbers 0 and 1 show that the variable c can alter the result independently while keeping the other two variables fixed. Test numbers 5 and 7 show that b can independently alter the value of the result. Test numbers 3 and 7 show that a can independently alter the result.

How Test Coverage Can Be Accomplished?

And the statement no. 3, 5 and 7 will be considered under Decision coverage. Additionally, NASA requires 100% MC/DC coverage for any safety critical software component in Section 3.7.4 of NPR 7150.2D. The statements marked in yellow color are those which are executed as per the scenario. Test coverage is also a requirement in part 6 of the automotive safety standard ISO Road Vehicles – Functional Safety. Test coverage is one consideration in the safety certification of avionics equipment. The guidelines by which avionics gear is certified by the Federal Aviation Administration is documented in DO-178B and DO-178C.