What is a branch in code coverage for JavaScript unit testing

If there is no explicitly defined default case, a branch region is generated to correspond to the implicit default case that is generated by the compiler. The implicit branch region is tied to the line and column number of the switch statement condition . In the example below, no explicit default case exists, and so a corresponding branch region for the implicit default case is created and tied to the switch condition on line 65.

definition of branch coverage

You can pass in an array containing any of the other filter types. The official formatter of SimpleCov is packaged as a separate gem called simplecov-html, but will be installed and configured automatically when you launch SimpleCov. Programming best practices suggest that a programmer provides such a method when writing a class. Infrastructure to adapt CPU_CYCLE monitoring to statement testing. Hardware counter, which is available on nearly every tablet, smartphone, and commodity computer.

1.8. Important Considerations for Branch Coverage¶

Summary-only – Export only summary information for each source file. Formatters besides the default HTML formatter require separate gems, however. Note that this only has to be invoked ONCE PER TEST SUITE, so even if you have 200 unit test files, specifying it in some_test.rb is enough. Primary coverage determines what will come in first all output, and the type of coverage to check if you don’t specify the type of coverage when customizing exit behavior (SimpleCov.minimum_coverage 90).

definition of branch coverage

For each t-way test plan, a random test plan of the same size was generated. The results show that in most cases, t-way testing performs better or as good as random testing; however, the differences are not as significant as expected. One explanation for this phenomena is that the random test plans had very high levels of t-way coverage, almost always over 80% and often over 95%. Two important notes with respect to the comparison between random and CT testing are as follows.

Use saved searches to filter your results more quickly

Both these features are known to denote hard optimization problems for all search–based optimization techniques. Last but not least if multiple suites resolve to the same command_name be aware that the coverage results will clobber each other instead of being merged. You can define your own to remove things like configuration files, tests or whatever you don’t need in your coverage report. It is important to note that depending on the generation method, random testing may not always be feasible. A random selection out of the Cartesian product of parameters and their values will most probably result in an invalid test case, i.e., a test case that does not satisfy the constraints.

With that being said it is generally accepted that 80% coverage is a good goal to aim for. Trying to reach a higher coverage might turn out to be costly, while not necessary producing enough benefit. In this case, if 4 cases are written matching the above logic statements, we would see 100% branch coverage. This helps developers from having to explicitly write out all 8 paths.

Branch Coverage: How It Differs From Similar Metrics

Structural testing techniques are those that, as the name suggests, are based upon the internal structure of the software being tested . Structural testing approaches are often referred to as white box or glass box. They are also sometimes referred to as Adequacy Criteria which reflects the perception of test data in terms of structural coverage criteria. For example, for a given program, if a set of test data exercises all statements then the set is described as being statement testing, or statement coverage, adequate. Extended THeME to execute tests while monitoring statement coverage.

This course of quality assurance is a vital part of the code validation, as these test cases not only cover the happy path it also covers the negative functional flow of the software application. Otherwise, the system will not know how to respond during the unexpected negative functionality. For example, in a login page of an application, https://www.globalcloudteam.com/ the user will enter the login id and respective password. In cases like an incorrect or blank username along with a password, the application needs to tell the user what went wrong and ask them to correct the error that they made. Hence the code needs to include the conditional statement for such failure scenarios.

Minimum coverage

For more details and a discussion of other coverage styles, see this reference. Comments about the glossary’s presentation and functionality should be sent to This site requires JavaScript to be enabled for complete site functionality. In case of a switch statement with more than two cases, it will be translated to switch() instruction with all the address in scopes and jumps to the relevant one according to the input.

  • However, search–based approaches degenerate to random testing in the presence of flag variables, because flags create spikes and plateaux in the fitness landscape.
  • Test coverage is one consideration in the safety certification of avionics equipment.
  • The resulting output is then analyzed to see what areas of code have not been exercised and the tests are updated to include these areas as necessary.
  • This simple string filter will remove all files that match “/test/” in their path.
  • Run your full test suite to see the percent coverage that your application has.
  • We can use the coverage toolistanbulto see how much of our code is executed when we run this script.

100% decision coverage implies both 100% branch coverage and 100% statement coverage. SimpleCov/Coverage track covered ruby code, gathering coverage for common templating solutions like erb, slim and haml is not supported. Since many different t-way test plans exist for each given strength t, do they all provide similar code coverage and are of similar sizes? In other words, how stable are t-way test plans in terms of code coverage and size?


Only caring about statement coverage can give teams a false sense of security when it comes to the comprehensiveness of their tests. As you’ll soon see, branch coverage is more nuanced than other metrics. A different metric can be at 100%, while branch coverage is lower. By only tracking the other metric, a team can have an unjustified degree of confidence in their code, and important defects might what is branch coverage in software testing go unnoticed until they manifest in production. Search–Based Testing is a widely studied technique for automatically generating test inputs, with the aim of reducing the cost of software engineering activities that rely upon testing. However, search–based approaches degenerate to random testing in the presence of flag variables, because flags create spikes and plateaux in the fitness landscape.

definition of branch coverage

In white box testing we examine the source code to derive test cases. There are a variety of techniques which vary in how thoroughly they exercise the code. A common term, “Test Coverage” refers to the degree of thoroughness or how well the suite of test cases “covers” or exercises the code. As you probably know, not all code coverage metrics are the same.

Types of Functional

Criterion defines TR to include all the branches in all the CFGs of the functions in the subject program. Thus, for T to satisfy branch coverage, T should exercise each branch of each control structure. For example, given an if statement, the body of the if should be executed in at least one instance and skipped in at least one other instance. Given an if-else, the body of the if should be executed in at least one instance and the body of the else executed in at least one other instance. And given a loop, it should iterate one or more times in at least one instance and zero times in at least one other instance. Many coverage tools report line coverage, which is probably the most basic coverage metric.