Test automation
At its simplest, test automation is a script that does what a manual tester would otherwise do by hand: perform a series of steps against an application, check whether the result matches what was expected, and report a pass or a fail. The steps themselves haven't changed, what's changed is who, or what, is carrying them out.
The reason it matters comes down to scale. Manual testing works fine for a handful of checks run occasionally, but it doesn't hold up against a fast release cadence. A regression suite that takes a full day to run by hand takes minutes once it's automated, and it can run on every single commit instead of once before a release, which is the difference between catching a problem in minutes and catching it days later after several more changes have piled on top of it.
Day to day, this spans several layers. Unit test frameworks built into a language check individual functions. API testing tools check a service's responses without a UI involved at all. Browser automation tools like Selenium, Playwright, or Cypress drive a real interface the way a user would. AI test automation is a newer evolution of the same idea, using AI agents to interpret an application's behavior instead of relying on scripts tied to one specific version of the interface.
Where automation typically fits
- Unit tests, checking a single function's output against expected values.
- API tests, checking a service's responses correctly without a UI in the loop.
- Browser and UI tests, using a tool like Selenium or Playwright to drive a real interface.
- Performance and load tests, simulating many users at once, something manual testing can't realistically do at all.
Where it shows up
- Running a full regression suite on every pull request instead of once a release.
- Checking that an API's responses stay correct after a backend change.
- Catching a UI regression across several browsers at once instead of testing each one by hand.
- Running a load test before a big launch to see how the system holds up under real traffic.
Benefits and challenges
| Benefit | Challenge |
|---|---|
| Runs the same check as many times as needed, on every commit, without extra cost per run. | Writing and maintaining the scripts is real, ongoing work, an automated suite isn't free just because it's automated. |
| Far faster than manual testing at any real scale, a suite that takes a day by hand can run in minutes. | A script tied to specific selectors or steps breaks when the interface changes, however small the change is. |
| Removes the inconsistency of a person running the same steps slightly differently each time. | Automation still can't judge some things as well as a person can, like whether a new design actually feels right to use. |
Frequently asked questions
Should everything be automated?
No. Automation pays off best on tests that run often and check something well-defined, like a regression suite. Exploratory testing, and anything that depends on human judgment, like whether an interface feels right, tends to stay manual, since automating it either isn't possible or isn't worth the effort.
What's the difference between test automation and AI test automation?
Traditional test automation runs scripts written against a specific version of an application, and breaks when that version changes. AI test automation uses AI agents to interpret an application's behavior instead of relying on fixed scripts, which lets tests adapt when the interface changes instead of failing.
What tools are commonly used for test automation?
It depends on the layer being tested. Selenium, Playwright, and Cypress are common for browser-based UI testing, unit testing usually relies on a framework built into the language itself, and API testing has its own dedicated tools separate from either of those.
How Klarent helps
Klarent's AI agents take on the maintenance that traditional test automation usually accumulates, generating tests from plain-language descriptions and repairing them automatically as the application changes, instead of leaving a team to rewrite scripts by hand.