Model-based testing: What is it about?

The Model-based testing approach is very useful when the projects/software are really complex, like many modules, program components, interactions (internal or external to software), steps, possibilities, etc. The model-based testing approach is an efficient way to test complex applications efficiently in a given time. 

Model-based automation testing can generate test cases automatically from applications that are very complex. It provides add-in benefits: scalability, robustness, and budget-friendly. The test cases are generated at early stages by considering the requirements specification or design. If the source code is used for generating test cases, the defects are unidentified. The popular tools used for MBT are Selenium and gauge. This technique is applied in the Microsoft company for testing. The Microsoft MBT tool is called Spec Explorer. You can explore more about Spec Explorer on this page: https://docs.microsoft.com/en-us/archive/msdn-magazine/2013/december/model-based-testing-an-introduction-to-model-based-testing-and-spec-explorer. 

Model-based testing is software testing where the run time behavior of the software will be checked against predictions that are made by the model. The model can be defined as the description of the system behavior, which describes in terms of input sequences, actions, etc.

There are a number of models available and it’s been described differently based on aspects of system behavior. Let us consider an example:

1. Data flow
2. Control flow
3. Dependency graphics
4. Decisions tables
5. State transition machines

Types of model-based testing:

1. Offline/prior: test case is collection of test steps, generation of test suites before it’s been executing
2. Online/on -the fly: this will generate test suites when the execution is been processed

Different models in testing:

It is important to understand some of the models, which is been listed:

1. Finite state machine: Finite state machine will help testers to assess the result which is depending on the input selected. There will be different combinations of inputs that will result in the corresponding state of the system. This will have a specific state and also a current state governed by a set of inputs from testers. 

Let us consider an example:

There is a system that will allow employees to get logged in to the application now. The current state of the employee is out and it has become in once he signs in to the system. When it is in the state, the employee will view the print scan document in the system.

2. Statecharts: this is the extension of finite state machines which can be used for complex and also real-time systems, these are used to describe different behaviors of a system. This will have a definite number of states, behavior is analyzed and represented in the form of events.

3. Unified modeling language: this will include a set of graphic notation techniques which will create visual models which will describe the complicated behavior of the system, it will have notations some of them are:

• Activities
• Actors
• Business process
• Components
• Programming language

  

Challenges of model-based testing:

Deployment of model-based testing is very important in every organization which obviously requires a high amount of investment and also effort.

Some of the disadvantages of model-based testing are:

1. It needs necessary skills which are required in testers
2. Learning time is more
3. Tough to understand the model

Advantages

1. Easy to write test cases
2. It will reduce in cost
3. It will improve test coverage
4. It will save time
5. It will improve tester job satisfaction
6. Suite the maintenance

Testers will build mental models during the testing, those models will be transformed into the models on the papers, this will help testers to achieve readability and also usability. Model-based testing will be the new approach so software which is shown below:

Model-checking: This will be used for test case generation; this was developed as a technique to check if the property specification is valid in the model. When it’s used for the testing model of the system under test and also a property to test will be provided to the model checker.

Questions

1. What is model-based testing? Explain briefly