What is integrationtesting?
Integration testing is a type of software testing where individual pieces of code (called modules or components) that have already been tested on their own are combined and tested together. The goal is to see if these parts work correctly when they interact with each other, just like checking if puzzle pieces fit together to form a complete picture.
Let's break it down
- Unit test: Test a single piece of code in isolation.
- Integration test: Take two or more pieces that already passed unit tests and run them together.
- System test: Test the whole application as a complete system. Think of it like building a LEGO set: first you test each brick (unit), then you connect bricks to build a wall (integration), and finally you look at the entire castle (system).
Why does it matter?
If components work alone but fail when combined, users will experience bugs that are hard to trace. Integration testing catches problems such as mismatched data formats, incorrect API calls, or timing issues early, saving time, money, and frustration later in development.
Where is it used?
- Web applications (frontend talks to backend APIs)
- Mobile apps (UI layer interacts with services)
- Micro‑service architectures (multiple services call each other)
- Embedded systems (sensor modules communicate with control software) Basically any software where separate parts need to communicate.
Good things about it
- Finds bugs that unit tests miss.
- Gives confidence that different modules work together.
- Helps define clear interfaces and contracts between components.
- Can be automated, allowing frequent checks in continuous integration pipelines.
Not-so-good things
- Can be slower and more complex to set up than unit tests.
- Requires realistic test data and environments, which may be hard to create.
- Failures can be harder to pinpoint because many components are involved.
- Over‑reliance on integration tests may lead to fewer focused unit tests, reducing overall test coverage.