Code Coverage Tutorial: Branch, Statement & Decision Testing
In this coverage, expressions with logical operands are only considered. In this method, the number of paths of executed branches is used to calculate Branch coverage. Branch coverage technique can be used as the alternative of decision coverage. Somewhere, it is not defined as an individual technique, but it is distinct from decision coverage and essential to test all branches of the control flow graph. It’s crucial to remember that even though branch coverage is a useful metric, it doesn’t always imply that your code is completely error-free.
- Some reports conclude that CT is more effective than random testing, for example, [99–102] in the context of logical expressions,  for a Flight Guidance System, and  for network-centric software.
- In contrast to other structural testing strategies which use control flow information to determine test criteria, data flow testing looks at the way that variables are used.
- Two important notes with respect to the comparison between random and CT testing are as follows.
- Despite these disadvantages, statement coverage is widely used in industry as a criterion for test quality [15,68–71].
- It provides various methods such as branch coverage, statement coverage,decision coverage, FSM coverage and more.
- This helps developers from having to explicitly write out all 8 paths.
In White Box Testing, the tester is concentrating on how the software works. In other words, the tester will be concentrating on the internal working of source code concerning control flow graphs or flow charts. In most cases, code coverage system gathers information about the running program.
Use coverage reports to identify critical misses in testing
Decision coverage implies statement coverage, because every statement is part of a branch. In the first case traversing through “Yes “decision, the path is A1-B2-C4-D6-E8, and the number of covered edges is 1, 2, 4, 5, 6 and 8 but edges 3 and 7 are not covered in this path. In the case of “No” decision the path is A1-B3-5-D7, and the number of covered edges is 3 and 7.
For code coverage evaluation, statement and branch coverage were measured. For each program, 100 t-way test plans were generated for each strength t ranging from 2 to 5. The PICT tool  was used to generate multiple t-way test plans by providing its greedy algorithm with different seeds. 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.
# . Reporting:
The HTML report gives information about which lines had missing branches. Lines
that were missing some branches are shown in yellow, with an annotation at the
far right showing branch destination line numbers that were not exercised. The higher the probability that defects will cause costly production failures, the more severe the level of coverage you need to choose. Statement coverage is used to derive scenario based upon the structure of the code under test. 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.
Code coverage can be decomposed into a number of different criteria, among which we have branch coverage. The complexity of the code will determine how many test cases are needed to achieve 100% branch coverage, which aims to evaluate all potential branches or decision points in the code. Therefore, as you begin your software testing projects, keep branch coverage in mind but also embrace the variety of tools in your testing toolbox to create reliable and robust software solutions. Some reports conclude that CT is more effective than random testing, for example, [99–102] in the context of logical expressions,  for a Flight Guidance System, and  for network-centric software. Other reports found no significant differences between random testing and CT [104, 105].
They start with performing static analysis of the source code and then use the information gathered during the search-based phase. They implemented their approach in a tool called SWAT, Search-based Web Application Tester and evaluated its effectiveness. Walcott-Justice  extended THeME to execute tests while monitoring statement coverage. In this work, the additional requirement was made that the source code cannot be modified in any way prior to execution.
It gives a clear view of the progress made in software application development. It is also called as ‘Decision Coverage’ method, as it involves the decision statements of the code. It can otherwise be explained as a necessity for validating the program’s ability to reach every nook and corner, in order to make certain that the functionality provided by the client is fulfilled. For instance, path coverage implies decision, statement and entry/exit coverage.
Branch vs. Line Coverage
Branch testing is a type of white-box testing that is used to test every possible branch in the control flow graph of a program. In branch testing, every branch in the code is executed at least once. https://www.globalcloudteam.com/ shows the percentage of the executed branches in the source code (normally, these are the if/else and switch statements).
This information is available for the JaCoCo runner and for the IntelliJ IDEA runner with the Tracing option enabled. The report shows the percentage of the code that has been executed or covered by tests. This is where the coverage reports can provide actionable guidance for your team. Most tools will allow you to dig into the coverage reports to see the actual items that weren’t covered by tests and then use that to identify critical parts of your application that still need to be tested. Unit tests consist in making sure that the individual methods of the classes and components used by your application are working. They’re generally cheap to implement and fast to run and give you an overall assurance that the basis of the platform is solid.
Find the right tool for your project
A site about programming languages, Technical topics And for codes too. In a flow graph, an arrow represents edges and counting a statement as a node, where two nodes are connected with an edge. Strategies for improving coverage are discussed in Improving Test Coverage.
This is reflected in coverage summary table that shows that only 2 out of 4 coverage bins were covered. The total number of coverage bins corresponds to the number of rows displayed in all the truth tables for the given conditional expressions. Indicates if each possible path in a given function was followed by the control flow. Branching points used to single out paths (see an explanation of this term in the previous table) are the same as in Decision (Branch) Coverage. Note that you need to double-click on a function to start off path coverage view.
It is often employed when testing individual objects (the localized maintenance of state being one of the central tenets of object-orientation) or other systems that implement state machines. Many candidates are rejected or down-leveled in technical interviews due to poor performance in behavioral or cultural fit interviews. Ace your interviews with this free course, where you will practice confidently tackling behavioral interview questions. A not-for-profit organization, IEEE is the world’s largest technical professional organization dedicated to advancing technology for the benefit of humanity.© Copyright 2023 IEEE – All rights reserved. Use of this web site signifies your agreement to the terms and conditions.