#mutationtesting — Public Fediverse posts

Ложное чувство защиты: Почему 90% code coverage не спасает от багов

90% code coverage выглядит как повод выдохнуть — до первого бага, который спокойно проходит сквозь все тесты и добирается до прода. В статье разберём, почему покрытие строк создаёт ложное чувство надёжности, чем branch coverage полезнее и как мутационное тестирование показывает реальные дыры в тестовом наборе. Разобраться в coverage

https://habr.com/ru/companies/otus/articles/1044658/

#qa #mutationtesting #покрытие_кода #мутационное_тестирование #автоматизированное_тестирование #качество_тестов

If you deleted all assertions, would your coverage drop? Probably not by much, and that’s the problem. Julius Mischok explains why #PIT mutation testing is the missing layer on top of JaCoCo.

Test your tests with PIT: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java #TDD #MutationTesting #JUnit5

If you deleted all assertions, would your coverage drop? Probably not by much, and that’s the problem. Julius Mischok explains why #PIT mutation testing is the missing layer on top of JaCoCo.

Test your tests with PIT: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java #TDD #MutationTesting #JUnit5

@jitterted Another helpful practice I like to use is #MutationTesting to ensure that my test is ACTUALLY catching errors that it should catch.

@jitterted Another helpful practice I like to use is #MutationTesting to ensure that my test is ACTUALLY catching errors that it should catch.

100% code coverage… and your tests still miss bugs? Julius Mischok shows why coverage measures execution, not verification — and how #MutationTesting with #PIT proves whether tests actually fail when code changes.

Add PIT + kill surviving mutants: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java

100% code coverage… and your tests still miss bugs? Julius Mischok shows why coverage measures execution, not verification — and how #MutationTesting with #PIT proves whether tests actually fail when code changes.

Add PIT + kill surviving mutants: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java

Deine Tests laufen bei jedem Build? Dann sind sie wichtig genug, getestet zu werden. Julius Mischok zeigt, wie #MutationTesting mit #PIT Schwachstellen in deiner #CI sichtbar macht.

Stärke deine Teststrategie: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#Java #CleanCode #DevOps #DevTools #JAVAPRO

Deine Tests laufen bei jedem Build? Dann sind sie wichtig genug, getestet zu werden. Julius Mischok zeigt, wie #MutationTesting mit #PIT Schwachstellen in deiner #CI sichtbar macht.

Stärke deine Teststrategie: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#Java #CleanCode #DevOps #DevTools #JAVAPRO

If you deleted all assertions, would your coverage drop? Probably not by much, and that’s the problem. Julius Mischok explains why #PIT mutation testing is the missing layer on top of JaCoCo.

Test your tests with PIT: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java #TDD #MutationTesting #JUnit5

If you deleted all assertions, would your coverage drop? Probably not by much, and that’s the problem. Julius Mischok explains why #PIT mutation testing is the missing layer on top of JaCoCo.

Test your tests with PIT: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java #TDD #MutationTesting #JUnit5

100% code coverage… and your tests still miss bugs? Julius Mischok shows why coverage measures execution, not verification — and how #MutationTesting with #PIT proves whether tests actually fail when code changes.

Add PIT + kill surviving mutants: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java

100% code coverage… and your tests still miss bugs? Julius Mischok shows why coverage measures execution, not verification — and how #MutationTesting with #PIT proves whether tests actually fail when code changes.

Add PIT + kill surviving mutants: https://javapro.io/2026/01/21/test-your-tests-mutation-testing-in-java-with-pit/

#Java

Deine Tests lügen. Und du glaubst ihnen. Nur #MutationTesting mit #PIT zeigt dir, wo Bugs unentdeckt bleiben. Julius Mischok erklärt, wie du überlebende Mutanten eliminierst.

Schlag zurück: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#MutationTesting #Java #CleanCode #DevOps #DevTools #JAVAPRO

Deine Tests lügen. Und du glaubst ihnen. Nur #MutationTesting mit #PIT zeigt dir, wo Bugs unentdeckt bleiben. Julius Mischok erklärt, wie du überlebende Mutanten eliminierst.

Schlag zurück: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#MutationTesting #Java #CleanCode #DevOps #DevTools #JAVAPRO

to check if software tests are working properly you can use #mutationtesting
it changes parts of your source code and reruns test. Ideally tests fail then, if not, then the software lacks some important tests
https://en.wikipedia.org/wiki/Mutation_testing

to check if software tests are working properly you can use #mutationtesting
it changes parts of your source code and reruns test. Ideally tests fail then, if not, then the software lacks some important tests
https://en.wikipedia.org/wiki/Mutation_testing

Vertraust du deinen Tests? Dann teste deine Tests. Mit #PIT deckt Julius Mischok auf, wo deine #UnitTests versagen – trotz 100 % Coverage.

Mutanten zeigen dir, wo’s weh tut. Lies jetzt: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#MutationTesting #Java #CleanCode #DevOps #DevTools #JAVAPRO

Vertraust du deinen Tests? Dann teste deine Tests. Mit #PIT deckt Julius Mischok auf, wo deine #UnitTests versagen – trotz 100 % Coverage.

Mutanten zeigen dir, wo’s weh tut. Lies jetzt: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#MutationTesting #Java #CleanCode #DevOps #DevTools #JAVAPRO

100 % Testabdeckung & trotzdem Bug im Code? Julius Mischok zeigt, warum #MutationTesting mit #PIT dein Vertrauen in Tests erschüttert & wie du es zurückgewinnst.

So deckst du echte Bugs auf: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#Java #CleanCode #DevOps #DevTools #UnitTesting #JAVAPRO

100 % Testabdeckung & trotzdem Bug im Code? Julius Mischok zeigt, warum #MutationTesting mit #PIT dein Vertrauen in Tests erschüttert & wie du es zurückgewinnst.

So deckst du echte Bugs auf: https://javapro.io/de/teste-deine-tests-mutation-testing-in-java-mit-pit/

#Java #CleanCode #DevOps #DevTools #UnitTesting #JAVAPRO

High coverage ≠ strong tests.
Mutation testing with Quarkus + PIT shows which tests really catch bugs.
Step-by-step tutorial for Java devs:
https://www.the-main-thread.com/p/mutation-testing-quarkus-java-tutorial

#Java #Quarkus #MutationTesting #Testing #PIT

High coverage ≠ strong tests.
Mutation testing with Quarkus + PIT shows which tests really catch bugs.
Step-by-step tutorial for Java devs:
https://www.the-main-thread.com/p/mutation-testing-quarkus-java-tutorial

#Java #Quarkus #MutationTesting #Testing #PIT

Released: @roave /infection-static-analysis-plugin 1.39.0

https://github.com/Roave/infection-static-analysis-plugin/releases/tag/1.39.0

Just upgrading `vimeo/psalm`, while we still work on upgrading `infection/infection` after numerous internal breaking changes in upstream. #php #mutationTesting

Released: @roave /infection-static-analysis-plugin 1.39.0

https://github.com/Roave/infection-static-analysis-plugin/releases/tag/1.39.0

Just upgrading `vimeo/psalm`, while we still work on upgrading `infection/infection` after numerous internal breaking changes in upstream. #php #mutationTesting

How can you use code coverage and mutation testing to add tests to legacy code? At @mendercon last year, I demonstrated this powerful technique step by step on the Gilded Rose kata, which is hosted by @emilybache on her GitHub account: https://github.com/emilybache/GildedRose-Refactoring-Kata

You can watch the talk here: https://www.youtube.com/watch?v=0qna5cuzDI0

#CSudberyRecordings #CodeCoverage #MutationTesting #GildedRose #Refactoring #UnitTests

How can you use code coverage and mutation testing to add tests to legacy code? At @mendercon last year, I demonstrated this powerful technique step by step on the Gilded Rose kata, which is hosted by @emilybache on her GitHub account: https://github.com/emilybache/GildedRose-Refactoring-Kata

You can watch the talk here: https://www.youtube.com/watch?v=0qna5cuzDI0

#CSudberyRecordings #CodeCoverage #MutationTesting #GildedRose #Refactoring #UnitTests

Nuevo post:

Usando conjuntamente ApprovalsJs y StrykerJS en WebStorm
https://codesai.com/posts/2025/06/usando-approvalsjs-y-strykerjs-en-webstorm

Suscríbete a nuestra newsletter: https://codesai.com/newsletter/

#legacy_code #mutationTesting #SoftwareEngineering #CodeQuality #Tech

Acabamos de publicar una traducción al español con algunas mejoras y actualizaciones de nuestro post sobre mutation testing "Relevant mutants":

Mutantes relevantes https://codesai.com/posts/2025/04/mutantes-relevantes

#testing #legacy #legacyCode #mutationtesting #tech #typescript #software #SoftwareEngineering

I’ve been a big fan of #MutationTesting since I discovered PIT. As I dive deeper into #Rust, I wanted to check the state of mutation testing in Rust.

https://blog.frankel.ch/mutation-testing-rust/

I’ve been a big fan of #MutationTesting since I discovered PIT. As I dive deeper into #Rust, I wanted to check the state of mutation testing in Rust.

https://blog.frankel.ch/mutation-testing-rust/

Republishing an old @codesai 's post on Dev community:

Relevant mutants
https://dev.to/trikitrok/relevant-mutants-3d67

@thepracticaldev

#legacycode #technicaldebt #cleancode #testing #SoftwareEngineering #TechDebt #CodeQuality #tech #DEVCommunity #mutationtesting

Thanks to all attendees of my evening session on #mutationtesting w/ #strykerNet at this year's .NET-Developers Conference #DDC in Cologne!
You can find the presentation here:
👉 https://draptik.github.io/2024-11-ddc-mutation-testing/
#dotNET

Thanks to all attendees of my evening session on #mutationtesting w/ #strykerNet at this year's .NET-Developers Conference #DDC in Cologne!
You can find the presentation here:
👉 https://draptik.github.io/2024-11-ddc-mutation-testing/
#dotNET

🚫 #AWS (#Amazon)
🚫 #Google (yeah, they have very talented developers, but still a big #privacy 🚩)
🚫 #Zoom, #MicrosoftTeams
🚫 Meta (#Facebook)
🚫 #AI/ #GenAI/ #GenerativeAI

✅ privacy
✅ code quality (#UnitTesting, #MutationTesting)
✅ CI/CD
✅ LAMP

🗺️ Hamburg (relocation possible to some extent)

👨🏻‍💻 Position: Full-stack web developer
👨🏻‍💻 Backend: #PHP (#Laravel)
👨🏻‍💻 Frontend: #HTML, #CSS, #JavaScript (#VueJS)

nice to have:
💚 #openSource
💚 #a11y
💚 #UX

#FediHire #GetFediHired

🚫 #AWS (#Amazon)
🚫 #Google (yeah, they have very talented developers, but still a big #privacy 🚩)
🚫 #Zoom, #MicrosoftTeams
🚫 Meta (#Facebook)
🚫 #AI/ #GenAI/ #GenerativeAI

✅ privacy
✅ code quality (#UnitTesting, #MutationTesting)
✅ CI/CD
✅ LAMP

🗺️ Hamburg (relocation possible to some extent)

👨🏻‍💻 Position: Full-stack web developer
👨🏻‍💻 Backend: #PHP (#Laravel)
👨🏻‍💻 Frontend: #HTML, #CSS, #JavaScript (#VueJS)

nice to have:
💚 #openSource
💚 #a11y
💚 #UX

#FediHire #GetFediHired

Back from #DWX24 - what a great conference!

Giving a session during the last slot on the last day is always challenging.
Both for the speaker as well as for the participants: After 3 days (& nights) everyone is exhausted :-)
Special thanks to all attendees of my session on "How to test your tests" (aka "Wir testen. Aber testen wir auch gut genug?")!
Slides: 👉 https://draptik.github.io/2024-07-dwx24-mutation-testing/1
(only the first 2 slides are german, the rest is EN)
#dotnet #stryker #mutationtesting

Back from #DWX24 - what a great conference!

Giving a session during the last slot on the last day is always challenging.
Both for the speaker as well as for the participants: After 3 days (& nights) everyone is exhausted :-)
Special thanks to all attendees of my session on "How to test your tests" (aka "Wir testen. Aber testen wir auch gut genug?")!
Slides: 👉 https://draptik.github.io/2024-07-dwx24-mutation-testing/1
(only the first 2 slides are german, the rest is EN)
#dotnet #stryker #mutationtesting

why do I love #barcamp s?
Because things like this happen: 2 people merge 2 talks on the spot.
#dotnet #javascript #testing #barcamp #socrates #franken
#socratesdayfranken #mutationtesting

why do I love #barcamp s?
Because things like this happen: 2 people merge 2 talks on the spot.
#dotnet #javascript #testing #barcamp #socrates #franken
#socratesdayfranken #mutationtesting

can somebody explain to me the purpose of the #stryker dashboard?

https://dashboard.stryker-mutator.io/

I don't get it?

What are the use-cases?

Here is a simple project (dotnet, using github-secret):

https://github.com/draptik/stryker-dashboard-demo

How can I use the so-called dashboard?

#mutationtesting #dotnet #JavaScript

can somebody explain to me the purpose of the #stryker dashboard?

https://dashboard.stryker-mutator.io/

I don't get it?

What are the use-cases?

Here is a simple project (dotnet, using github-secret):

https://github.com/draptik/stryker-dashboard-demo

How can I use the so-called dashboard?

#mutationtesting #dotnet #JavaScript

In a previous life, I was a big fan of #mutationtesting.

I found these two crates in #Rust for this:

* cargo-mutants: https://mutants.rs/
* mutagen: https://github.com/llogiq/mutagen

Has anybody any experience with any of them? Or something else?

In a previous life, I was a big fan of #mutationtesting.

I found these two crates in #Rust for this:

* cargo-mutants: https://mutants.rs/
* mutagen: https://github.com/llogiq/mutagen

Has anybody any experience with any of them? Or something else?

Folks, who uses #MutationTesting in work or personal projects?

How do you like it? Do you find it useful? Interesting? Boring? Annoying? Tell me!