Software Testing Approaches

Here, we are going to learn about the various software testing approaches, their advantages and disadvantages.
Submitted by Rahul Gupta, on March 08, 2021

Software testing approaches are the methods that give a direction to software testers or programmers to test programming code using an appropriate method. In this article, we are going to learn about various software testing methods and their significances in a programming environment.

The various approaches of software testing are as follows -

1) Static Testing

Static testing is a White Box testing method in which developers validate or review code for fault detection.

Static testing is a method of reviewing the code and designing documentation and specifications before it is run to detect bugs instead of running the code. In the early steps of production, the key objective is to identify weaknesses. The causes of potential failures are usually easier to find in this way.

Static testing is undertaken for the following reasons:

Detection and correction of early defects.
Reduced timescales for growth.
Reduced cost and time of testing.
Enhancing the efficiency of production.
To get fewer defects at a subsequent step of testing.

The other major type of software testing, dynamic testing includes the testing at the time of code execution at run time. To try to maintain the basic functionality of a program, the two strategies are often used together.

Static Testing using Tools

Following are the types of defects detected by the tools during static testing:

A vector with a value unknown.
The inconsistent interface between components and modules.
Declared but never used variables.
Unreachable (or) Dead Code code.
Violations of programming standards.
Protection flaws.
Grammar breaches.

The method of evaluating a computer program to identify problems without ever running, it is static testing and also called static code testing. Static testing is more commonly conducted on the program's source code with tools that transform a program into an Abstract Syntax Tree (AST) to explain the structure of the code and then identify issues in it.

Advantages of Static Testing

It can locate vulnerabilities at the exact position in the code.
Trained software assurance developers who completely understand the code will perform it.
Other or potential developers can easily understand the source code.
This enables a faster turn time for fixes error.
Weaknesses are detected earlier in the life cycle of production, minimizing the cost of fixing them.

2) Dynamic Testing

Dynamic Testing is a technique in software testing used to assess software code's dynamic behaviour. The main aim of dynamic testing is to test software actions in the software runtime environment with dynamic variables or variables that are not constant and to identify weak areas. To evaluate the dynamic actions, the code has to be executed.

We all know that testing is all about the verification and validation, and completion of testing involves 2 Vs. Of the 2 Vs, verification is referred to as a static test and the other "V" is known as dynamic testing

Features of Dynamic Testing

By knowing its characteristics and various other elements, the value of software testing methods can be achieved. Hence, some of the features of dynamic testing are described below.

It helps detect software defects.
Determines the code's consistency attributes.
It allows the team to find software glitches and bottlenecks.
Testing is achieved by the program being executed.
Supports the team in validating the software product's accuracy.

3) Black Box Testing

Black box testing means to test a device without advanced knowledge of its internal workings. Input is given by a tester, and the output produced by the device under test is observed. This makes it possible to recognize how the system reacts, its response time, usability problems and reliability problems to planned and unexpected user behaviour.

Black box testing is an effective testing technique; it is a method which exercised end-to-end code. A tester will simulate user behaviour to see if the system fulfills its commitments, just as end-users don't care how a system is coded or architected, and expect to receive a suitable response to their requests. All related subsystems, including UI/UX, web server or application server, database, dependencies, and integrated systems are tested along the way by a black-box test.

Black Box Testing Techniques

Followings are the Black Box Testing Techniques -

Equivalence Class Partitioning: Partitioning of equivalence is a technique based on the premise that a program's inputs can be partitioned into data classes (a set of valid/invalid input conditions states). This is an important form of black-box testing and gives a description of how it is extracted from test cases. This technique is helpful to avoid duplication and reduce the number of test cases that need to be created.
Boundary Value Testing: It is one of the useful and important techniques of Black box testing that assists in partitioning equivalence. BVA allows assessing any program with boundary values or extreme values. Instead of concentrating on the input value set, this approach is capable of finding the weaknesses in the limits of the input values. Edge or extreme performance values are often taken care of through Boundary Value Testing.
State Transition Testing: In some systems, significant responses are generated when the system transitions from one state to another. A common example is a login mechanism that allows users to authenticate, but after a specific number of login attempts, a transition to a different state, locking the account. If testers identify a state transition mechanism, they can design test cases that probe the system during transition states.
For example, for a system that locks the account after five failed login attempts, a test case can check what happens at the sixth login attempt.
Significant responses are produced in some systems when the system transitions from one state to another. A typical instance is a login mechanism that enables users to authenticate but move to a different state, locking the account after a certain number of login attempts.
If a state transfer process is defined by testers, they may build test cases that test the system as it switches states. For example, a test case may check what occurs at the sixth login attempt for a system that locks the account after five failed login attempts.
Cause-Effect Graphing: Cause-effect graphing is a tool that takes into account the desired external behavior of a program. It demonstrates the relationship between effects and causes graphically. It describes all the variables that affect the specific outcome, to do this, Test cases are accordingly planned.
Decision Table Testing: This approach is similar to the methodology of graph-based testing; instead of using table diagrams or graphs.
Error Guessing: Error guessing is a black box technique that relies exclusively on the tester's previous experience. To assess where errors in the software might be, the software tester uses their previous experience. Test cases are then configured to detect those mistakes and any recurrent bugs.

Advantages of Black Box Testing

Black box experiments are often done from the point of view of a consumer because it will greatly help to reveal inconsistencies.
Black-box testers do not need to understand any programming languages, either.
Black-box testers do not need to understand how the program has been applied.
As soon as the requirements are at the last step, test cases relevant to the black box are designed by testers.

Disadvantages of Black Box Testing

Tests can be unnecessary if the software designer is already running them.
Without simple and concise requirements, test cases are extremely hard to design.
It is not practical to evaluate every possible input stream because it is time-consuming and this will inevitably leave several program paths untested.
Reports may often be overestimated.
It cannot be used to evaluate complicated code fragments.

4) White Box Testing

Software methodology consists of black-box testing and white box testing. White box testing, also known as glass box testing, structural testing, clear box testing, open box testing and transparent box testing. It checks the internal coding and software infrastructure for the control of predefined inputs against planned and desired outputs. It is based on an application's inner workings and revolves around the testing of internal frameworks. Programming skills are required for the design of test cases in this form of testing. The primary objective of white-box testing is to concentrate on the software flow of inputs and outputs and improve the software's security.

White Box Testing Techniques

Followings are the White Box Testing Techniques.

Statement Coverage: Statement coverage is a technique of white box testing that ensures that all executable statements in the code are executed at least once. For instance, if there are many conditions in a code block, each of which is used for a certain input range, every input range should be executed by the test to ensure that all lines of code are executed.
Branch Coverage: This technique tests each potential direction of a software application (if-else and other conditional loops). There are various types of coverage, apart from the aforementioned, such as condition coverage, multiple condition coverage, route coverage, feature coverage, etc. Each approach has its own merits and attempts to test all components of the software code.
Path Coverage: Coverage of the route means that each path is traversed at least once. For the testing of complex systems, this approach is used.

White box Testing Tools

net: This is a tool for JavaScript testing. JUnit is a component of Junit and its testing system for open-source units that can be used for White Box Testing. Under GNU Public License 2.0, JSUnit is entirely open source, which means that a developer does not have to pay any licensing fee, except for commercial use.
Veracode: Veracode is a popular toolkit that helps rapidly, economically and efficiently recognizes and correct defects. This supports different programming languages such as .NET, C++, JAVA, etc. Security monitoring also supports it.
CppUnit: CppUnit is often considered to be a member of JUnit, much like JUnit. Depending on the needs of the tester, the tool can execute in plain text or XML format and can construct unit tests of its classes. Under the LGPL, CppUnit is licensed.
Google tests: Google C++ test system has an extensive list of features such as Discovery test, Death tests; Value parameterized tests, fatal & non-fatal failures, generation of the XML test report, etc. It supports different frameworks, such as Linux, Windows, Symbian, Mac OS X, etc.
NUnit: It's a framework for unit testing and it was written in C#. All available .Net languages are supported by the tool and it also supports data-driven testing. In terms of features, it can operate on both parallel and concurrent execution and can include a class structure and runner apps for testing. One of NUnit's noteworthy characteristics is that it is fairly simple to use.

Advantages of White Box Testing

Optimization of code by discovering hidden errors.
Cases of white-box testing can be effectively automated.
As all code paths are normally protected, testing is more rigorous.
In SDLC, testing can begin early, even if the interface is not available.

Disadvantages of White Box Testing

White box-testing, when it comes to large-scale programming applications, requires so much time.
Testing for white boxes is very costly and complicated.
It may lead to an error in production because the developers do not detail it.
White box testing includes experienced programmers who have a comprehensive knowledge and understanding of the vocabulary and application of programming.

5) Grey Box Testing

Grey box testing is a type of software testing with partial knowledge of the internal operating framework to test the software application. It is a mixture of a black box and white box testing as it provides access to internal coding to build test cases as white box testing and testing procedures are conducted as black-box testing at the functionality step.

Techniques of Grey box Testing

Followings are the Gray Box Testing Techniques -

Matrix Testing: In matrix testing, the developers describe all of the application's variables. There are market and technological risks associated with each of these variables. Matrix testing aids in the discovery of unused variables.
Regression Testing: Regression testing is used to ensure that no harmful or unwanted effects in any other aspect of the software have been triggered by improvements in any part of the software. Every defect was fixed during validation testing, and that part of the software began to function as expected, however, there may be a risk that a fixed defect may have introduced a different defect somewhere else in the software. Regression testing, therefore, takes care of these types of defects by assessing techniques such as re-testing unsafe use cases, re-testing inside a firewall, re-testing everything, etc.
Orthogonal Array Testing: It is a technique for black-box testing. It is helpful in testing situations where the input set is relatively small but too large to fit every possible input combination for rigorous testing. This technique helps to recognize regional flaws (single mode faults, double mode faults, multimode faults). Due to defective logic in the software component, regional faults occur. Orthogonal array testing, with a relatively limited number of test cases, offers full test coverage.
Pattern Testing: Pattern testing applies to the software that is generated in compliance with the same pattern as previous software. The same type of defects will occur in these types of software. Pattern testing discovers the reasons for the failure so that the next program can correct them.

Advantages of Grey Box Testing

With a partial understanding of the code, testers perform grey box testing from the viewpoint of the end-user. This helps to find any problems that may have been overlooked by the developers during unit testing.
Grey box testing results in the immediate fixing of the problems as the partially available code can be modified by a tester to search for the results.
Also without high-level programming abilities, this can be performed by the testers.
Awareness of the system's internal mechanisms allows the tester to more thoroughly develop test scenarios.
Functional requirements and other design documents are used for grey box testing; it does not require the use of source code to help keep the source code safe from any disruptive changes.

Disadvantages of Grey Box Testing

Defect identification is difficult for distributed systems when grey testing is performed.
Restricted access to the internal framework results in limited access for traversal of code paths.
Since the source code cannot be reached, it is not possible to do white box testing.
For algorithm testing, Grey Box Testing is not acceptable.
It is difficult to design most of the test cases.

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