typelevel/scalacheck

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Property-based testing for Scala

Stars: 2k
Forks: 393
Open beginner issues: 0
Indexed issues: 56
Avg merge: 6h 42m
Merged PRs (30d): 4

Dominant language: Scala
License: BSD-3-Clause
Last GitHub push: Sep 9, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted

Beginner friendly Everything

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56 open issues indexed

Seed.apply has different result on Scala 2 and 3 Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 58/100

typelevel/scalacheck#1209 · Opened Sep 16, 2026
Forked-run detection fails on sbt 2, reinstating #185: property failures reported as passed, exit 0 Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

typelevel/scalacheck#1195 · 1 reaction · Opened Aug 20, 2026
Support live visualizations with Tyche, via the `OpenPBTStats` log format? Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

typelevel/scalacheck#1078 · 4 comments · 1 reaction · Opened Oct 26, 2024
Publish javadoc with dependency Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

typelevel/scalacheck#1043 · Opened Mar 19, 2024
Partition a finite collection? Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

typelevel/scalacheck#1028 · Opened Jan 4, 2024
Add edge cases to Gen.choose[BigInt] Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#993 · Opened Jul 29, 2023
Feature request: automatically persist failure cases and prioritise their reproduction in the following test runs. Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

typelevel/scalacheck#970 · 1 comment · 1 reaction · Opened Jun 7, 2023
Feature request: lazy labels Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#969 · 1 comment · Opened Jun 6, 2023
Shrinking goes into semi-infinite recursion Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 28/100

typelevel/scalacheck#968 · 1 comment · Opened Jun 6, 2023
Gen of Associative Functions Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#907 · 1 reaction · Opened Jul 14, 2022
Shrink should put its smallest guesses first Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

typelevel/scalacheck#801 · 1 comment · 1 reaction · Opened Apr 28, 2021
Return efficient strategies for simple filter predicates, instead of rejection sampling Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

typelevel/scalacheck#755 · Opened Feb 4, 2021
Tuple shrinking should go to 11 (and beyond) Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#738 · 4 comments · Opened Dec 22, 2020
Future of the commands API Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

typelevel/scalacheck#737 · 2 comments · Opened Dec 21, 2020
Integer shrinking is less efficient than it could be. Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

typelevel/scalacheck#735 · 7 comments · Opened Dec 21, 2020
Shrinking command data Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#728 · 1 comment · Opened Dec 6, 2020
Expose Gens for BigDecimal with provided scale Open

Difficulty 2/5 1-3 hours Newbie friendliness 32/100

typelevel/scalacheck#692 · 1 comment · 1 reaction · Opened Oct 24, 2020
Add scalacheck examples to shrinking challenge Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#676 · Opened Aug 18, 2020
JUnit Platform engine Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#628 · 6 comments · 1 reaction · Opened Feb 16, 2020
Add java.lang.Integer as Default Arbitrary Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#615 · 1 comment · Opened Jan 30, 2020
Populate initial state from the SUT Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

typelevel/scalacheck#582 · Opened Nov 6, 2019
CanBuildFrom/GenTraversableFactory causing serialization issue Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

typelevel/scalacheck#579 · 4 comments · Opened Oct 24, 2019
ConsoleReporter reports 0% frequencies due to rounding Open

good first issue help wanted

Difficulty 3/5 1-2 days Newbie friendliness 45/100

typelevel/scalacheck#576 · Opened Oct 9, 2019
Suggestion: add method to define a flat list of classify conditions to collect statistics on Prop Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#566 · 2 comments · Opened Sep 26, 2019
Can't use overrideParameters Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#533 · Opened Sep 1, 2019
Longer output with viewSeed Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#532 · 1 comment · Opened Sep 1, 2019
Gen.sequence ignores size of given Traversable Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

typelevel/scalacheck#483 · Opened Jun 29, 2019
don't shrink for Exceptions Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

typelevel/scalacheck#462 · Opened Mar 20, 2019
Generators library Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#456 · 5 comments · 3 reactions · Opened Feb 19, 2019
Arbitrary, Gen and Choose instances for primitive types should respect size Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#448 · 4 comments · Opened Jan 17, 2019
Shrinking shrinks a List required to be nonEmpty to Nil Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

typelevel/scalacheck#443 · 3 comments · Opened Nov 30, 2018
Shrinking an argument will regenerate and reshrink subsequent arguments Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

typelevel/scalacheck#432 · 6 comments · Opened Oct 3, 2018
Display more helpful failure information in Commands API Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#426 · 1 comment · 5 reactions · Opened Sep 16, 2018
forAll with ||, and exists with &&, can be inconsistent Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

typelevel/scalacheck#425 · 10 comments · Opened Sep 15, 2018
PropertySpecifier.update Prop arg is repeatedly reevaluated. Bug or Feature? Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

typelevel/scalacheck#424 · 2 comments · Opened Sep 14, 2018
Overloaded Prop.collect behaves surprisingly with Seq[T] argument Open

Difficulty 1/5 Under an hour Newbie friendliness 35/100

typelevel/scalacheck#421 · 2 comments · Opened Sep 11, 2018
retryUntil fails to produce anything when used to check list size inside a Prop Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#413 · 2 comments · Opened Jun 5, 2018
Generating a list of size N where each element is distinct. Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

typelevel/scalacheck#352 · 7 comments · 2 reactions · Opened Aug 10, 2017
Add ?!= and other methods to simplify creating comparison properties Open

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

typelevel/scalacheck#322 · 1 comment · Opened Mar 17, 2017
Tests generating invalid inputs (value 0) Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#317 · 7 comments · 1 reaction · Opened Mar 5, 2017
Generate non serializable collection Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#315 · Opened Jan 28, 2017
trees in scalacheck Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

typelevel/scalacheck#305 · 13 comments · 1 reaction · Opened Dec 1, 2016
Properties no longer extends Prop; there is no straightforward way to check all of a Properties group pass Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

typelevel/scalacheck#254 · 4 comments · Opened Aug 17, 2016
Stack overflow caused by retryUntil Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

typelevel/scalacheck#232 · 1 comment · Opened Apr 8, 2016
Testing timed automata Open

Difficulty 5/5 Over a week Newbie friendliness 15/100

typelevel/scalacheck#223 · Opened Feb 21, 2016
Help with stateful testing Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

typelevel/scalacheck#199 · 14 comments · 3 reactions · Opened Oct 25, 2015
Properties("") tests are suffering of deadlock to static scala initializers Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

typelevel/scalacheck#155 · Opened Mar 25, 2015
Make class declarations public to enable save and replay of shrinked command sequences Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

typelevel/scalacheck#143 · 3 comments · Opened Feb 9, 2015
Make :| lazy Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

typelevel/scalacheck#140 · 1 comment · Opened Jan 26, 2015
Example of beforeAll & afterAll Open

Difficulty 3/5 1-2 days Newbie friendliness 28/100

typelevel/scalacheck#134 · 2 comments · 1 reaction · Opened Jan 15, 2015

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