coregex

A handy utility for generating strings that match given regular expression criteria.

Supported generators

• functionaljava-quickcheck
• Jqwik
• JUnit Quickcheck
• Kotest
• scalacheck
• vavr-test

Usage

You can use this library directly by compiling an instance of coregex from any given regular expression pattern:

var pattern = Pattern.compile("[a-zA-Z]{3}");

var coregex = Coregex.from(pattern);

Having an instance of coregex, you can ask it to generate a string matching original regular expression. At any given time this should be true:

var seed = ThreadLocalRandom.current().nextLong();

assert pattern.matcher(coregex.generate(seed)).matches();

Given the library is primarily intended to be used in property based testing, it comes with a set of integrations for popular property based testing frameworks.

Functionaljava Quickcheck

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-functionaljava-quickcheck"

Use the provided CoregexArbirary class to generate a string that would match the regular expression predicate:

@RunWith(PropertyTestRunner.class)
public class MyTest {
  private static final Pattern PATTERN = Pattern.compile("[a-zA-Z]{3}");

  public Property myProperty() {
    return property(CoregexArbitrary.gen(PATTERN), CoregexArbitrary.shrink(PATTERN), str -> prop(3 == str.length()));
  }
}

Jqwik

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-jqwik"

Use the provided Regex annotation to generate a string that would match the regular expression predicate:

class MyTest {
  @Property
  void myProperty(@ForAll @Regex("[a-zA-Z]{3}") String str) {
    assertThat(str).hasLength(3);
  }
}

JUnit Quickcheck

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-junit-quickcheck"

Use the provided Regex annotation to generate a string that would match the regular expression predicate:

@RunWith(JUnitQuickcheck.class)
public class MyTest {
  @Property
  public void myProperty(@Regex("[a-zA-Z]{3}") String str) {
    assertThat(str).hasLength(3);
  }
}

Kotest

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-kotest"

Use the provided CoregexArbirary class to generate a string that would match the regular expression predicate:

class MyTest : DescribeSpec({
  describe("my property") {
    it("should hold") {
      checkAll(CoregexArbitrary.of("[a-zA-Z]{3}")) { str ->
        str.length shouldBe 3
      }
    }
  }
})

scalacheck

Include the following dependency into your project:

libraryDependencies ++= Seq("com.github.simy4.coregex" %% "coregex-scalacheck" % Test)

Use the provided CoregexInstances trait to constrain string arbitraries:

object MySpecification extends Properties("MySpecification") with CoregexInstances {
  property("my property") = forAll { (str: StringMatching["[a-zA-Z]{3}"]) =>
    3 == str.length  
  }
}

vavr test

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-vavr-test"

Use the provided CoregexArbirary class to generate a string that would match the regular expression predicate:

class MyTest {
  @Test
  void myProperty() {
    Property.def("my property")
        .forAll(CoregexArbitrary.of("[a-zA-Z]{3}"))
        .suchThat(str -> 3 == str.length())
        .check();
  }
}

ZIO test

Include the following dependency into your project:

testImplementation "com.github.simy4.coregex:coregex-zio-test"

Use the provided CoregexGen class to generate a string that would match the regular expression predicate:

object MySpec extends ZIOSpecDefault {
  def spec = suite("my spec")(
    test("my property") {
      check(CoregexGen.from(Pattern.compile("[a-zA-Z]{3}"))) { str => 
        assertTrue(str.length == 3)
      }
    }
  )
}