Just wonder what the difference is. I need some concise explanation.The wikipedia is a bit too verbose for me.
Regression testing is actually a test suite that is supposed to test as much functionality of your application as possible.
The idea is that, when you make a change to your application as required for bug fixing or new functionality, regression testing will hopefully catch any problems (or regressions) with your changes.
It's called regression since the vast majority of tests have been added due to previous bugs hence, if they find a problem, you have regressed to a previous state (in which the problem once again exists).
In other words, regression testing tests your application.
Mutation testing is actually introducing small errors (called mutations) into your application (errors that are not supposed to fix bugs or provide new functionality) to see if your test suite picks them up.
The idea is that, if your test suite doesn't pick up the mutations, it is deficient and should have more test cases added.
In other words, mutation testing tests your test suite rather than your application.