Beginner’s guide to regression testing
In December 2018 more than 30 million O2 customers were left without Internet access after an internal update. A tiny error at the UK telecommunications company caused a nationwide outage and disrupted electronic timetables at London bus stops.
This error could’ve been easily avoided with some regression testing.
Changes to the application code can introduce unintentional side effects called regressions. Often, they can affect the app’s functionality or performance.
Imagine changing a tire on your car making the steering much harder or breaking your air conditioner.
Regression testing is, therefore, aimed at finding issues caused by changes to the code. It is critical for the overall stability and performance of your app.
In practice, this means re-running a select number of old test cases to verify that the new functionality doesn’t break old features (not to be confused with re-testing which is simply running the same tests for the second time after a bug fix to ensure the defect was indeed removed).
Among the main benefits of regression testing are:
- Earlier detection of bugs caused by changes to the system.
- Focus on building new features instead of reworking old defects.
- Better UX without unintended side effects.
- Less unexpected risks.
- Improved system performance, etc.
Now, how do you perform regression testing? Let’s find out!