White Box Testing Techniques

SOFTWARE ENGINEERING NOTES PART 4 WHITE BOX TESTING TECHNIQUES BASIS PATH TESTING Basis path testing is a white box testing technique proposed by McCabe in 1980. This testing is used to design test cases and in this the flow or logical path of the program is used to design test cases. This testing ensures that all flow or logical path of the program is executed at least once. (It uses McCabe's cyclomatic complexity for this.) The basis path testing consists of the following posts:1: - First of all, the control flow graph is made to determine the different paths of the program. 2: - (to determine the independent paths) cyclomatic complexity is calculated. 3:- A basis group of paths is searched. 4: - Finally test cases are generated for each path. Basis path testing helps us to determine all the errors present in the code of the program. SOFTWARE REQUIREMENT SPECIFICATION AND ITS CHARACTERSTICS Software requirement specification is a complete document or description of the requirements of a system or software application. That is, in other words, "SRS is a document that describes what will be the features of the software and what will be its behavior ie how it will perform." The advantage of SRS is that it takes less time and effort for the developers to develop the software. SRS is like the layout of the software which the user can review and see whether it (SRS) is made according to his needs or not. We learned about the software requirement specification, what it is, now let's read its features. characteristics of SRS in hindi (Features):- Following are the characteristics of this:1:- accurate 2:- clear 3:- complete 4:- consistent 5:- verifiable 6:- modifiable 7:- traceable 8:- testable 9:unambiguous 10:- correct 1:- Complete (Complete):- The SRS which is there should be complete i.e. all the software requirements should be mentioned in the SRS. 2:- Correct (proper):- It should be correct, that is, it should be according to the needs of the customer. 3:- Clear:- It should be clear. The requirements of the software should be clearly stated. 4: - Accurate: - There should be accuracy in this. If this is not accurate then the software cannot be built. 5: - Consistent: - It should be consistent from beginning to end so that users can easily understand the requirements. And consistency can be achieved only when there is no contradiction between the two requirements. 6:- Verifiable:- It should be verifiable. The requirements are verified by the experts and testers. 7:- Modifiable:- All the requirements specified in the SRS document should be modifiable. This can happen only when the structure of SRS is balanced. 8: - Traceable: - It should be traceable, that is, each requirement in it should be identified differently. Each requirement should have its own unique identity. 9: - Testable: - It should be testable, that is, it should be able to be tested in any way. 10: - Unambiguous: - It can be unambiguous only when all the requirements have only one meaning. That is, there should be only one interpretation. DATA FLOW DIAGRAM A data flow diagram is a graphical representation of the flow of data passing through an information system. As its name suggests, it only focuses on the flow of data (information), where the data came from, where it will go, and how it will be stored. The data flow diagram is used to create an overview of the software system. The data flow diagram presents the incoming (input) data flow, outgoing (output) data flow and stored data in a graphical form, but DFD does not explain its process in detail. But there is a flow chart for this. Both flow chart and DFD are different topics. Types of DFDs There are two types of DFD. 1:- Logical DFD 2: - Physical DFD 1:- Logical DFD:- Logical DFD focuses on the business activity, that is, it focuses on the flow of data in the system and the process of the system. 2: - Physical DFD: - Physical DFD focuses on how the data flow is actually implemented in the system. Data flow diagram was first used in the 1970s and it was described by larry constantine and Ed yourdon. DFD components:- DFD has the following four main components. 1:-entities 2:- data storage 3:- Processes 4:- data flow 1: - Entities: - The source and destination of data are called entities. Entities are displayed by rectangle. 2: - Data storage: - A place where data is stored. It is represented by a rectangle that does not have one side or does not have both sides. 3:- Process:- This is a task which is done by the system. It is represented by a circle or a round-edged rectangle. 4: - Data flow: - It shows the movement (speed) of the data. This is represented by an arrow. SOFTWARE CASE TOOLS WHAT IS CASE? The full name of CASE is computer aided software engineering, it is a software that supports one or more software engineering activities in the process of creating software. Simply put, "case means that automated software tools will be used to build and maintain the software." CASE is used a lot to develop software because its functionality and potential is very good, which increases the quality of software. CASE tools:- Case tools are a set of software applications that automate the activities of the Software Development Life Cycle (SDLC). Case tools are used by software engineers, software managers, and testers to develop software. Case tools support most of the phases of SDLC such as: - Design, Testing, Coding etc. That is, case tools are used in all these phases. Which ensure that the quality of the software is high, there are no defects in it, and the software development work is done in any way in less time and cost. Case tools are also used for debugging and managing data. Case tools were first manufactured in the 1980s. The purpose of proposing CASE tools was to reduce the time and cost of developing software and to improve the quality of software. components of case tools:Following are the components of this. 1:- upper case tools 2:- lower case tools 3:- integrated case tools 1: - Upper case tools: - Upper case tools are used in the earlier phases of software development. These tools are used in planning, analysis and design phase. 2: - Lower case tools: - These case tools are used in the later phases of software development, implementation, testing, and maintenance. 3: - Integration case tools: - It is also called I-CASE. These tools can be used in all phases of SDLC. types of case tools:Its types are as follows:- 1: - Diagramming tools: - These tools are used to represent system processes, data and control structures and system components in the form of pictures. 2: - Analysis tools: - These tools are used to analyze diagrams, forms and reports. 3:- Design tools:- Design tools are used by software designers to design the software structure. 4: - Process modeling tools: - These tools are used to create and change the process model of the software. 5: - Project management tools: - These tools are used for coding. That is, these tools help in creating software projects. 6: - Quality tools: - These tools are used to improve the quality of the software. 7: - Maintenance tools: - When the software is created, then it needs to be maintained and changes are also made over time. Maintenance tools are used to do this work. 8: - Prototyping tools: - These tools are used to give a new look to the software and style it well. There are many graphics in these tools which make the user interface and design good. STRESS TESTING Stress testing is used to test the stability and reliability of the system. It is a non functional testing technique which is a part of performance testing. In stress testing, by overloading the system, it is verified and checked whether the system is able to withstand the stress or not. This test mainly determines how robust the system is and how the system handles errors even under heavy load. Stress testing is also done to ensure that the system will not crash in times of crisis. Stress testing is also called endurance testing and torture testing. Why is stress testing done? Following are the reasons for doing this testing:To check the performance of the system. To verify whether the system saves the data when it crashes or not. To check whether the system shows an error message when it crashes or not. To check whether the security remains intact or not when a system failure occurs. How is stress testing done? Many users run the system at the same time. All users perform difficult operations on the system at the same time. All users open a file at the same time. RAD MODEL The full name of RAD model is rapid application development model. The methodology of the RAD model is the same as that of the incremental or waterfall model. It is used for small projects. If the project is big then it is divided into many small projects and these small projects are planned one by one and they are completed. In this way, by completing small projects, the big project gets ready quickly. In RAD model, the project is completed within the given time and all the requirements are gathered before starting the project. In RAD model, the project is completed very fast and errors are also very less in it. The main objective of RAD model is to reuse code, components, tools, processes in project development. The RAD model has the following phases: business modeling data modeling process modeling application generation testing and turnover 1:- business modeling:- In this phase, the business model of the product is designed on the basis of the information received from various business activities. Before starting the development work, the complete business information and functionality is thoroughly analyzed. 2: - Data modeling: - When the business modeling phase is over, the information obtained from business modeling is used to define data objects. 3: - Process modeling: - The data objects that were defined in data modeling are transformed to obtain the information flow so that some specific business goals (goals) can be met based on the business model. 4: - Application generation: - In this phase the application is created and coding is done. And automated tools are used for creating and coding software. All this happens in real time. 5: - Testing and turnover: - In this all interfaces and components are tested. Since in this the prototype is tested separately in each cycle due to which the testing time in RAD decreases. Advantage of RAD model:Its benefits are as follows:1:- It reduces the time taken in development. 2: - In this the components are reused. 3: - It is flexible and it is easy to make any changes in it. 4: - It is easy to transfer like scripts because high level abstraction and intermediate codes are used in it. 5:- Defects are very less in this because it is a prototype by nature. 6:- In this, productivity can be increased in less time with less people. 7: - It is cost effective. 8: - It is suitable for small projects. Disadvantages of RAD model:Its disadvantages are as follows:1: - In this we need highly skilled developers and designers. 2:- It is very difficult to manage it. 3:- It is not suitable for long lasting and big projects. 4:- In this, the feedback of the client is required for the development of each phase. 5: - Automated code generation is very expensive. 6: - This model is only suitable for component based and scalable systems. COHESION AND COUPLING If software design is good then software quality is better and there are many ways to analyze software design like-coupling, cohesion, factoring, system shape etc. CohesionCohesion is a measurement that defines the degree of intra-dependability of elements within a module. That is, in cohesion it is seen how closely the elements of a module are related to each other. That is, how deep is the relationship of the elements of the modules with each other. The more cohesion, the better the software design will be. The higher the cohesion of the module, the less the coupling between modules. Cohesion is of the following types. 1- coincidental 2- logical 3- Temporal 4- Procedural 5- communicational 6- Sequential 7- functional 1- Coincidental cohesion- This cohesion is the lowest level of cohesion. This happens when there is no relationship between the elements of the module. This happens when the program is broken into smaller modules. 2- Logical cohesion- Logical cohesion in a module occurs when there is a logical relationship between the elements of a module. And elements perform the functions placed in the same logical class. 3- Temporal cohesion- This cohesion is like logical cohesion but in this the elements should be executed at the same time. Temporal cohesion is of a higher level than logical cohesion because elements are processed at the same time. 4- Procedural cohesion- When the elements of the module are grouped together, they are executed in a sequence to complete a task, this is called procedural cohesion. 5- Communicational cohesion- When the elements of the module are grouped together which are executed in sequence to complete a task and all these elements work on data (information) at the same time then it is called communicational cohesion. 6- Sequential Cohesion- When the elements of the module are together in a group because the output of one element is like the input for the other element, then we get sequential cohesion. 7- Functional cohesion - This is the highest level of cohesion, all the elements of the module are related to performing a function. CouplingCoupling is a measurement that defines the level of inter-dependability between modules of a program. That is, it is a type of measurement that defines how the components of the software depend and interact with each other. The less the coupling, the better the software design. Types of coupling Coupling is of the following types: 1- content coupling 2- common coupling 3- external coupling 4- control coupling 5- stamp coupling 6- data coupling 1- Content Coupling- Content Coupling which is the highest level of coupling, occurs when a module is dependent on the internal mechanism of another module. This means that if there is any change in the second module, then there will be a change in that dependent module as well. 2- Common coupling- It is also called global coupling, it occurs when the same global data is shared by two modules. There will be changes in both the modules when changes are made in the global data. 3- External coupling- This type of coupling occurs when external data format and communication protocol are shared by two modules. 4- Control coupling- In this type of coupling, one module controls the flow of another module and sends data from one module to another. 5- Stamp coupling – In this type of coupling, many modules share the same type of data structure and work in different parts of it. 6- Data coupling- Data coupling between two modules will happen when the data will pass only between them.