What is Intergration testing and its type.

Integration testing is a type of testing that helps in analyzing the communication between two modules. Integration tests can reveal flaws in the interaction between integrated parts. Once unit testing was completed, an integration test was carried out.

Integration testing can be divided into two main categories:
 

The Big Bang Approach: 

The incremental approach, which is further divided into the following:

2.1. Top Down Approach

2.2. Bottom Up Approach

Big Bang Testing:-

Big Bang Testing is an approach that seeks to improve in which all of the components or modules are linked at the same time and then verified as a unit. During testing, this integrated set of components is treated as a single object. The integration operation will not run unless  all of the components in the unit have been accomplished.

Advantages : 

1. Suitable for small systems.

Disadvantages: 

1. Localizing faults is challenging.
2. Given the large number of interfaces that must be examined in this method, certain interfaces that must be evaluated may be overlooked.
3. Because integration testing can only begin once "all" of the modules have been designed, the testing team will have less time for testing execution.

Incremental Approach
Modules are added in ascending order one by one or as needed in the incremental approach. The modules chosen must be logically related.

Top-Down Approach
What exactly is a top-down approach? A top-down approach involves disassembling a system into its constituent subsystems. The procedure can be repeated to deconstruct subsystems into low-level elements such as classes and methods.

Advantages

1. Appropriate for applications that use the bottom-up design methodology.
2. If major flaws occur near the end of the programme, this is advantageous.
3. It is simpler to create test conditions.
4. Disadvantages
5. A partially integrated system does not allow test engineers to observe system level functions. They are unable to observe system-level functions until the top-level test driver is installed.
6. The programme does not exist as an entity until the last module is added.

Bottom-Up Approach

1. The bottom to up testing strategy addresses the process of testing lower level modules with higher level modules until all modules have been successfully tested. Because top-level critical modules are tested last, a defect may occur. Alternatively, we can say that we will add the modules from bottom to top and test the data flow in the same order.
2. Advantages
3. It is simple to identify a flaw.
4. It saves time not to have to wait for the development of all modules.
5. Disadvantages
6. Because critical modules are tested last, defects may occur.
7. An early prototype is not a possibility.