Kill the mutants, test your tests

We all write unit tests and we measure the quality of the tests with line coverage or (even better) branch coverage… But this is wrong, it gives you a false sense of security. I’ve seen tests that have 100% coverage but not a single assertion!This is where mutation testing helps out. By creating broken ‘mutated’ instances of your codebase (mutants) this should result in failing unit tests. This way we can verify that slight code changes (like real life bugs) actually break your tests.In this talk I’ll explain what mutation testing is and how you can use it. I’ll show and compare some Java frameworks (PIT, Jester, Jumble) that enable (automatic) mutation testing in your project, from local build to continuous integration. After this talk you can and will start using mutation testing!

Roy van Rijn
Roy van Rijn, a software Craftsman at JPoint ( Before starting JPoint, Roy was Java Software Architect at Ordina, working on miscellaneous projects and giving roadshow presentations around the Netherlands. He was also co-author of the book “Software Ontwikkeling in Java EE”. He has regularly given trainings during his career, including Spring, Sofware Architecture, Testing and Agile/Lean courses. Currently he is involved with the HaMIS project by the Port of Rotterdam. A very succesful Scrum project, which hasn’t just changed the development team, but the whole project management structure underneath resulting in a hyper-productive project.
Video Rating: / 5

LSAT Prep by Kyle Pasewark, founder of Advise-In Solutions. Go to

Kyle Pasewark, a Yale Law J.D. and perfect 180 scorer on the LSAT, founded Advise-In Solutions to help law school applicants and students secure their highest LSAT score, and their best law school admissions, law school financial aid and legal employment results. All Advise-In programs—from LSAT preparation to law school admission and law school application advising, law school “boot camp”, employment advising and law firm associate orientation—are custom-designed for each client. All Advise-In clients work directly with Kyle, who has been advising and teaching pre-law students for over a decade. So that each LSAT client receives all the personal attention needed to obtain their best LSAT score, Kyle accepts a limited number of LSAT clients in each exam cycle.

Find out more about Advise-In’s one-on-one LSAT prep program for your best LSAT score at, or contact Advise-In Solutions at 212-249-2718 or by e-mail at
Video Rating: / 5

21 thoughts on “Kill the mutants, test your tests”

  1. Hey everyone! Prospective law student here. I was wondering how many hours you put into studying daily/weekly? If you feel like being extra descriptive, elaborate on your study schedule and whatnot. Thanks so much, and good luck (or good job)!!!

  2. I am a high school senior whose dream is to attend an ivy league law school in 4 years. Is there anything I can start doing now, and in my first years of college, to prepare for the LSAT?

  3. Hi Kyle,
    Thank you for your advice. I heard from another person who scored a 180 that they took a LOT of preptests (2-3 a day) with review. Is this what you personally did/recemmend? Do you think this is a good idea for people who are willing to handle the workload, and review the tests the same way you suggest? I think my accuracy is good in the sense that when I'm finished with my test I am able to correctly identify my incorrect answers and why I got them wrong. I'm currently in the 161-165 range and I was hoping you could maybe give me some advice on how I can take it to the next level. Thank you

  4. Having a data bank of results, patterns and questions used combined with saved info on the assessments of how I came to conclusions is actually genius.

  5. When taking practice exams for the LSAT, it would be very important to know why you missed the questions you did. That would better prepare you for the real exam.

  6. You don't need a tutor to get a perfect score. In fact most people who have gotten a perfect score have done so without a tutor. What you do need is ferocious self-motivation and drive throughout your study. Starting slow is fine. In fact it is optimal. Get the concepts down completely first. Don't start doing timed work until you have a high rate of accuracy. Then it all comes down to practice, practice, practice. The more questions you do the faster and more comfortable you will get.

  7. You can get a perfect score, it just requires getting a pretty good score and having a lot of luck on the questions that make you think to yourself "Who the fuck writes these?". Especially the really long winded, terminology laden questions that were obviously written by a former Bio student. I hate those the most. The logic of those questions gets lost in the distinction between Osmotic pressure and Osmotic gradient.

  8. you need your brain wired to think in the way the LSAT is designed. Its a program, and you have to disassemble it. If you neeeeed adderall then you shouldn't be pursuing law.

  9. Kind of a joke – you won't get a perfect score if you understand anything about the LSAT, especially if it takes you a long time because that's the point, it's a speed test. Lastly, you might want to spell correctly for your essay portion – it's advice, not advise!!!

Leave a Reply

Your email address will not be published. Required fields are marked *