What Is Branch Coverage & What Does It Really Tell You?

By taking more lines of code to do the same thing, we actually increased our code coverage numbers! If you are paying a lot of attention to the code coverage numbers, then you don’t want your code coverage percentages to change depending on how many lines of code you use to write a function. Code coverage percentages should be related to the complexity of the code. So, by taking more lines of code to do the same thing, we actually increased our code coverage numbers! If you are paying a lot of attention to the code coverage numbers, then you don’t want your code coverage percentages to change depending on how many lines of code you use to write a function. It helps to determine the minimum number of test cases you need to comprehensively test a given piece of code.

definition of branch coverage

Most developers understand this process and agree on its value proposition, and often target 100% coverage. Although 100% coverage is an admirable goal, 100% of the wrong type of coverage can lead to problems. A typical software development effort measures coverage in terms of the number of either statements or branches to be tested.

Parts of speech for Branch coverage testing

Basis path testing is for instance a method of achieving complete branch coverage without achieving complete path coverage. CodeGuru covers topics related to Microsoft-related software development, mobile development, database management, and web application programming. Cloud services such as Microsoft Azure and database options including SQL Server and MSSQL are also frequently covered.

White-box testing verifies code according to design specifications and uncovers application vulnerabilities. Among the most popular code coverage tools are Cobertura, JTest, Clover, Emma, and Kalistick. Every result from a code module is tested in the branch coverage. In the preceding source code, for example, if the input values are 2 and 3, the ‘Else’ section of the code will not be run. The ‘If’ part of the code, on the other hand, will not be run if the input values are of types 3 and 2.

definition of branch coverage

The ultimate goal of any software development company is to provide high-quality software. The software must be properly tested in order to reach this goal. Next, you can create one JUnit test case that satisfies the requirement and gets 100% statement coverage. The main purpose of the Branch Coverage Testing is to make sure every functional test scenario has the ability to cover all the potential branching for functional looping statements.

Introduction to Branch Coverage

Needs to review the security of your connection before proceeding. Let us consider the below example for the execution of the Branch Coverage Testing process. Applying it reduces the likelihood of edge case defects making it into production. For example, if the outcomes are binary, you need to test both True and False outcomes.

  • When each occurring condition in the source code is assessed for both true and false states, the code’s Condition Coverage is said to be complete.
  • An appending virus is a type of virus that adds its code to the end of the file of a host program.
  • Path coverage, on the other hand, is a more robust and comprehensive technique that helps reveal defects early.
  • It aids in determining whether present testing is adequate and whether additional tests are required.
  • When relying upon code coverage numbers, you obviously do not want your code coverage percentages to change depending on how many lines of code you use to write a function.
  • Branch coverage is also known as Decision coverage or all-edges coverage.

This testing method is applicable only to operations other than the Boolean operations, for which the outcome will either be true or false. It’s important for you to understand that, no matter how good a metric is, it doesn’t tell you everything. Also, Goodhart’s Law—or, more specifically, the generalization of it made by Marilyn Strathern—warns you that any metric that becomes a target loses its value as a metric. After that, we’ll delve deeper into the concept of branch coverage. We’ll provide examples, explaining the ways in which this metric can be useful.

In other words, achieving a high coverage—branch or otherwise—is the bare minimum you could do. It still doesn’t guarantee you have quality tests or that your code behaves as expected. Also, it might help you cover areas that didn’t get adequate coverage from different testing methods. Let’s understand this with an example, how to calculate statement coverage. Statement coverage is used to derive scenario based upon the structure of the code under test. Function coverage will be satisfied if, during this execution, the function foo was called at least once.

How to calculate Branch coverage?

However, this set of tests does not satisfy branch coverage since neither case will meet the if condition. 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.

A binary tree is a tree data structure where each node has up to two child nodes, creating the branches of the tree. Parent nodes are nodes with children, while child nodes may include references to their parents. Code coverage does not tell you whether we tested all of a feature’s conceivable values. EMMA provides coverage at the class, method, line, and base block levels, as well as at the aggregated source file, class, and method levels. Code coverage does not allow us to tell whether we tested all possible values for a feature.

This is done to guarantee that each component of the code being tested functions properly. If we were to draw the path taken by Test 2_2, it would be a straight line from the read statement down the False exit and through definition of branch coverage the ENDIF. We could also have chosen other numbers to achieve either the True or False outcomes. Let’s suppose that we already have the following test, which gives us 100% statement coverage for code sample 4.3.

definition of branch coverage

It also combines this information with source code information to provide a report on the code coverage of the test suite. As a result, testing is an important aspect of the software development process. As a result, it’s critical that the software generated be evaluated by the developer and then delivered to the QC team to be extensively tested to guarantee that it has few or no flaws. The primary value ofbranch coverageis to measure how much of yourprogram’s structureis being exercised by your tests.

Creating Test Data

It covers all the possible outcomes of each condition of decision point at least once. Branch coverage technique is a whitebox testing technique that ensures that every branch of each decision point must be executed. A code coverage metric that is too broad will miss opportunities to highlight uncovered code. Hopefully, this article gives you a good understanding of how branch coverage is calculated and why it’s a better overall metric than the line/statement/sequence-point coverage metrics.

Combined with other test coverage methods, the aim is to develop a rigorous, yet manageable, set of regression tests. Branch Coverage is a white box testing method in which every outcome from a code module is tested. The purpose of branch coverage is to ensure that each decision condition from every branch is executed at least once. It helps to measure fractions of independent code segments and to find out sections having no branches.

Cyclomatic complexity helps you define the number of linearly independent paths, called the basis set, through a method. As a type of tactical testing, branch coverage testing is more of a https://globalcloudteam.com/ metric used to gauge testing outcomes than a testing philosophy or broader-based testing strategy idea. By nature, branch coverage testing is different than other broader forms of testing.

How to Calculate Branch Coverage?

This methodology measures the extent to which the functions included in the source code are covered during testing, as the name implies. During the test run, all functions in the source code are tested. Again, we must ensure that we test these functions for varied values in order to guarantee that the function is adequately tested. Not only does this reduce the number of basis paths that you need to test, but it reduces the number of decisions along each path.

Flow Chart of Above Code

A test method which aims to ensure that each possible branch from each decision point (e.g. “if” statement) is executed at least once, thus ensuring that all reachable code is executed. Before we answer that question, let’s have a look at another way to represent this code. Sometimes the decision structure is easier to see in a control flow diagram (see Figure 4.4). Branch Coverage is sometimes also described as saying that each branch condition must have been true at least once and false at least once during testing. It uses a control flow graph to calculate the number of branches. Else FunctionB();
This is obviously a very simple example and the number of branches, and the overall complexity of the code, can quickly grow as additional conditions are introduced.

It is one form of white box testing which finds the areas of the program not exercised by a set of test cases. It also creates some test cases to increase coverage and determining a quantitative measure of code coverage. Paths within it; loop constructs can result in an infinite number of paths. Many paths may also be infeasible, in that there is no input to the program under test that can cause that particular path to be executed. However, a general-purpose algorithm for identifying infeasible paths has been proven to be impossible .

Why use Code Coverage?

This sounds great because it takes a more in-depth view of the source code than simple statement coverage, but branch coverage can also leave you wanting more. However, you can see that in Example 2 we introduced more lines of code to accomplish the same outcome. This increased the total number of sequence points and the overall sequence point coverage from 70% to 75%. When relying upon code coverage numbers, you obviously do not want your code coverage percentages to change depending on how many lines of code you use to write a function. Code coverage percentages should be related to the complexity of the code, hence the need for the branch coverage metric. Code coverage is a metric that describes how thoroughly the program’s source code has been tested.

With these methods, it is possible to achieve nearly 100% code coverage in most software projects. 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.

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