Integration Testing Vs. Functional Testing

Integration Testing Vs. Functional Testing
Integration and functional testing are two phases in the software testing process. The former is undertaken after unit testing, while the latter is a black box testing technique. This Techspirited post undertakes an integration vs. functional testing comparison to understand these methodologies better.
Techspirited Staff
Do Not Get Confused
Functional testing is also referred to as E2E testing or browser testing. Integration testing can be considered as an extension of unit testing.

The software product development and testing cycle can be a never-ending labyrinth, comprising innumerable stages and strategies. Software testing is a vital phase after development as it is important to test a process or component from every perspective before releasing the final product to the client. There are different methods and levels in which components can be tested.
Two major testing methodologies include the box-technique and the static and dynamic testing technique, which comprise a number of further testing types and levels. Integration testing can be classified as a testing level, while functional testing can be considered a testing type. The paragraphs to follow comprise further details regarding these terms and also explain the difference between integration and functional testing.
Integration Testing
  • Integration testing can be defined as testing how smoothly the different modules of the system work together.
  • At length, it refers to the integrated functioning of the different modules, rather different components of the system.
  • For any system or software product to work efficiently, every component has to be in sync with each other. Integration testing tools strive to connect and integrate the different parts of the software to coexist and work without errors.
  • The tools used for integration testing are the same as those used for unit testing, though it takes a while for the test database to get configured.
  • It is used in complex situations, when unit testing proves to be insufficient to test the system.
Functional Testing
  • Functional testing can be defined as testing the individual functionality of modules.
  • It refers to testing the software product at an individual level, to check its functionality.
  • It is very different from unit or integration testing; you cannot write innumerable test cases for functional testing, since it is more complex than unit testing.
  • Functional testing tools strive to test the functionality of the software. Then, test cases are developed to check the software for expected and unexpected results.
  • This type of testing is carried out more from a user perspective. That is to say, it considers the expectation of the user for a type of input.
  • Selenium is one of the most common tools used for functional testing.
Integration Testing Vs. Functional Testing
Integration Testing Functional Testing
It tests integrated functionality and compatibility. It tests individual functionality.
Its purpose is to check the overall performance of the system; the test cases check the accuracy of the interaction between the various groups of components. Its purpose is to check the individual performance of every module. The test cases are written to check the functionality against the expected performance specification.
The test cases are written for the end-user, but are read and analyzed by design experts―software design domain experts. As mentioned earlier, they are written from a customer or end-user's perspective; considering his/her requirements and expectations.
  1. Top-Down testing
  2. Bottom-Up testing
  3. Sandwiched testing
  4. Big-bang testing
  1. Sanity testing
  2. Smoke testing
  3. Regression testing
  4. Usability testing
Consider a rather simple example of an office database. This database contains information of employees from various departments, each of which have an individual database system. Thus, while every departmental database functions individually, the data from all of them are linked to the main database. Integration testing, in this case, will test the compatibility of these databases with each other so that they are linked effectively and provide the right output to the end-user. Assume that you are testing a simple text editing application. Functional testing of this application would involve testing the functionality of tasks, like typing, editing tools, saving and opening files, formatting, printing, etc.
The process of testing is one of the most important phases in the software development life cycle as it enables developers to unearth errors and bugs. It is through testing that they are aware of whether the code has been written correctly, what changes need to be implemented, and how they need to be implemented so that the final output is error-free and user-friendly.