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Decision Coverage Testing in SDLC

In this article, I am going to discuss Decision Coverage Testing in SDLC. Please read our previous article where we discussed Statement Coverage Testing. At the end of this article, you will understand the following important pointers which are related to Decision Coverage Testing in SDLC.

1. What is Decision Coverage Testing?
2. How are Decision Coverage Tests Conducted?
3. How is Decision Coverage Calculated?
4. Examples to Understand Decision Coverage Testing
5. What are the Advantages of Decision Coverage Testing?
6. What are the Disadvantages of Decision Coverage Testing?

What is Decision Coverage Testing?

A testing technique called decision coverage or branch coverage seeks to guarantee that every feasible branch from every decision point is performed at least once, guaranteeing the execution of all reachable code. A white box testing method called Decision Coverage reports the true or false results of each Boolean expression in the source code. By checking and confirming that each branch of each potential decision point is run at least once, decision coverage testing aims to cover and validate all the accessible source codes.

Expressions in this coverage can occasionally get difficult. Therefore, achieving 100% coverage is exceedingly challenging. Because of this, there are numerous ways to report this measure. These approaches are all centered on covering the most significant combinations. It offers more sensitivity to control flow than decision coverage, although being extremely comparable to it. Below is the formula:

Decision Coverage = (No of Decision outcome exercised)/ (total No of Decision Outcomes) * 100

How are Decision Coverage Tests Conducted?

Every single line of the program is supposed to go through Decision Coverage Testing, which finds any potential decision-making streams in the codes. It is well recognized that this stage of code testing is crucial to the process of creating programs and developing applications. Skipping this stage can seriously reduce the effectiveness of the program in that module. The performance of the application will be significantly impacted by any failure or flaw discovered during the Decision Coverage testing.

• The end-to-end execution of the program is scanned in the decision coverage testing’s initial stage in order to find the decision indications scattered throughout the code. Here, the decisions are nothing more than the code that has more than one possible result, can have more than one execution flow path, and can ultimately result in the production of one or more products.
• The following phases entail putting together a logical decision-making flowchart and listing the outcomes of the numerous choices made and incorporated into the application’s code. Given that a single consistent code execution sequence doesn’t require any logical decisions to be taken, it is likely to have more than one conclusion.
• The evaluation of the logical decision indicators gathered and created in the preceding parts of this testing process is the last and most important step in the Decision Coverage testing procedure. The various logic endpoints are put through the requisite validation and verification procedures. If the obtained end result agrees with the intended result, which must be directly related to the information provided by the customer in the form of functional specification documents, the testing process is said to have been successful.

How is Decision Coverage Calculated?

Application program code must undergo Decision Coverage Testing in order to validate every conceivable logical and functional flow and guarantee the program’s flawlessness. Additionally, this procedure is utilized to verify that the program is running as intended and that the operations carried out within it are accurate. The Decision Coverage evaluation is given a numerical number using the formula below.

Decision Coverage = (No of Decision outcome exercised)/ (total No of Decision Outcomes) * 100

where the number of logical decisions counted in the program will determine the total number of decisions, and the number of decisions implemented from those decisions will provide the Decision Coverage Percentage value.

Examples to Understand Decision Coverage Testing:

The example code below demonstrates that the ‘if’ condition produces many decisions.

Test (int x)
{
if(x>4)
x=x*3
Print (x)
}
The value of an x in scenario 1 is 7 (x=7).
The value of x is 7 (x=7)
Test (int x=7)
{
if (x>4)
x=x*3
print (x)
}
The outcome of this code is “True” if condition (x>4) is checked. Control flow graph when the value of x is 7.

Decision Coverage = ½*100 (Only “True” is exercised)
                                   =100/2
                                   = 50
Decision Coverage is 50%

The value of an x in scenario 2 is 3 (x=3):
Test (int x=3)
{
if (x>4)
x=x*3
print (x)
}
The result of this code is? False? if the (x>4) condition is true. Control flow diagram when an x = 3

= ½*100 (Only “False” is exercised)
=100/2
= 50
Decision Coverage = 50%

Result Table:

Test Case	Value of x	Output	Decision Coverage
1	3	3	50%
2	7	21	50%

What are the Advantages of Decision Coverage Testing?

A method used in software testing to assess the thoroughness of test cases is decision coverage testing, sometimes referred to as branch coverage testing. It focuses on making sure that each program decision point has been tested at least once. The following are the benefits of decision coverage testing:

1. Enhanced Test Coverage: Decision coverage testing ensures that every branch within a decision point is used, which increases the chance of finding flaws and vulnerabilities.
2. Improved Quality: By making sure that every decision point is verified, decision coverage testing helps find potential boundary conditions, unusual instances, and logic flaws, thus improving the software’s overall quality.
3. Chance Reduction: By exercising all decision points during decision coverage testing, the chance of catastrophic failures or untested paths that could result in software bugs or security breaches is decreased.
4. Decision coverage testing is frequently necessary for safety-sensitive or regulated businesses to verify compliance with norms and laws, and it serves as proof of meticulous testing efforts.
5. Debugging Aid: Decision coverage testing helps to identify and isolate mistakes by testing each decision point, which speeds up and improves the debugging process.

What are the Disadvantages of Decision Coverage Testing?

Although decision coverage testing has certain advantages, it also has some drawbacks.

1. Complete path coverage is not guaranteed by decision coverage; it merely ensures that each decision or branch is executed. There could be several untested paths in a choice, which could result in errors that go undiscovered.
2. Time and Resource Consumption: Obtaining thorough decision coverage can take a lot of time and resources, especially for intricate software systems. Every decision can need significant effort to create and carry out tests, which can affect the testing’s overall timetable.
3. Limited Fault Detection: Although decision coverage testing aids in the discovery of potential flaws in decision structures, it cannot ensure the discovery of all program flaws. It could be essential to conduct additional testing, such as boundary testing or mutation testing, to supplement decision coverage.
4. Decision coverage typically focuses on evaluating various control flow options while ignoring potential problems with data flow and data dependencies. Focus on Control Flow, Not Data Flow. This restriction may result in insufficient coverage of problems relating to data.
5. Challenges with Maintenance: Maintaining decision coverage can be difficult when software changes and evolves. The test suite may need to be updated and maintained frequently if decision structures are changed or new features are added.

In the next article, I am going to discuss Decision Table in Testing. Here, in this article, I try to explain Decision Coverage Testing in SDLC. I hope you enjoy this Decision Coverage Testing article.