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If there are 1000 lines of code but only 100 tests, then your coverage might not be very good. On the other hand, if there are 100 lines of code but 1000 tests, then the test coverage is probably quite good. First, it only applies to lines of code that are actually executed when the tests are run. So, if there are 1000 lines of code but only 500 are executed when the tests are run, then the test coverage would be 50%. But overall if you see, all the statements are being covered by both scenarios.

decision condition coverage testing

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.

Condition Decision Coverage criteria(CDC) for software testing

Decision Coverage Evaluation acts as a crucial test coverage method as this code coverage method is one step above other coverage testing methods. It gives a better perception of the operations hidden under the program against the functionality that is expected by the client. As it can include the Boolean operations, it is most often chosen over the Branch coverage process. Decision coverage is a frequently used code testing method which is used to validate the exposure of the limitations of various decision trees in the program. The decision trees are typically derived from the conditional statements, the looping statements and the Boolean expressions or values in the program. The testing process in this case is carried out by validating all the possible execution flow through the said conditions and looping statements.

decision condition coverage testing

Decision coverage, also known as branch coverage, is a testing technique that ensures that each possible branch from each decision point is tested at least once, ensuring that all reachable code is executed. Generally, a decision point has two decision values one is true, and another is false that’s why most of the times the total number of outcomes is two. The percent of decision coverage can be found by dividing the number of exercised outcome with the total number of outcomes and multiplied by 100.

Statement Coverage

The purpose of test coverage is to ensure that all code paths in a program are executed at least once during testing. This helps to ensure that all bugs and potential problems are found and fixed before the program is released. Test coverage can be measured in a number of ways, but the most common metric is line coverage, which simply measures the percentage of lines of code that are executed during testing. Condition/decision coverage requires that both decision and condition coverage be satisfied. However, for safety-critical applications it is often required that modified condition/decision coverage (MC/DC) be satisfied. This criterion extends condition/decision criteria with requirements that each condition should affect the decision outcome independently.

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.

Multiple condition coverage

Statement Coverage is a white box testing technique in which all the executable statements in the source code are executed at least once. It is used for calculation of the number of statements in source code which have been executed. The main purpose of Statement Coverage is to cover all the possible paths, lines and statements in source code.

With a combination of C1 and C2, it is possible to cover most statements in a code base. Statement coverage would also cover function coverage with entry and exit, loop, path, state flow, control flow and data flow coverage. With these methods, it is possible to achieve nearly 100% code coverage in most software projects.

Examples to Implement of Decision Coverage

Decision Coverage is a white box testing technique which reports the true or false outcomes of each boolean expression of the source code. The goal of decision coverage testing is to cover and validate all the accessible source code by checking and ensuring that each branch of every possible decision point is executed at least once. Decision coverage technique comes under white box testing which gives decision coverage to Boolean values. This technique reports true and false outcomes of Boolean expressions.

  • The target software is built with special options or libraries and run under a controlled environment, to map every executed function to the function points in the source code.
  • Here it is relevant to vary in the outcome of the decision, and in the outcomes of the conditions.
  • Modified Condition/Decision Coverage (MC/DC) is a method used in software testing to test highly critical systems.
  • But overall if you see, all the statements are being covered by both scenarios.
  • This technique focuses on having a more in-depth test of complex conditions that represent the underlying rules for a decision in a control flow graph.

It is used to determine the total number of executed statements in the source code based on the total number of statements in the source code. This code coverage testing method is used as abet to maintain the quality of the program and the logical decisions employed on it. Finite state machine coverage is certainly the most complex type of code coverage method. In this coverage method, you need to look for how many time-specific states are visited, transited. It also checks how many sequences are included in a finite state machine.

Advantages of MCDC 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.

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.

Which Type of Code Coverage to Choose

Generally, test coverage tools incur computation and logging in addition to the actual program thereby slowing down the application, so typically this analysis is not done in production. 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. Paths within it; loop constructs can result in an infinite number of paths.