"Testing" is an umbrella over many specialised activities. Understanding the main types helps you pick the right one for a given risk or goal.
Functional types
- Smoke testing — a quick check that the build is stable enough to test.
- Sanity testing — a narrow check that a specific fix or feature works.
- Regression testing — confirming existing features still work after changes.
- Retesting — re-running tests on a defect that was supposedly fixed.
Non-functional types
- Performance — speed, throughput, and stability under load.
- Security — resistance to misuse and attack.
- Usability — how easy and pleasant the software is to use.
- Compatibility — behaviour across browsers, devices, and platforms.
| Type | Question it answers | Typical timing |
|---|---|---|
| Smoke | Is the build testable? | Start of a test cycle |
| Regression | Did we break anything? | After every change |
| Performance | Is it fast and stable? | After functional sign-off |
| Security | Is it safe? | Throughout, before release |
Note: the same feature may be covered by several types — a login screen can be functionally tested, performance tested, and security tested, each revealing different risks.
Conclusion
There is no single kind of testing — there is a toolbox. Knowing the types and what each reveals lets you build a strategy that targets the risks that matter most for your product.