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withIO

withIO

If you just run IO.unsafeRunSync() in a test, it may not end and just hang. extras for hedgehog and cats-effect 3 (extras-hedgehog-ce3) can solve it with withIO.

def withIO(test: => Ticker => Result): Result

To use withIO, your test needs to import extras.hedgehog.ce3.syntax.runner

import hedgehog.runner._
import extras.hedgehog.ce3.syntax.runner._

object SomeSpec extends Properties {

then in your test, use withIO like

def test: Result = 
withIO { implicit ticker =>
// Your test
val exected = ??? // A
val actual = ??? // IO[A]
actual.completeThen(_ ==== expected)
}

or

def test: Property =
for {
n <- Gen.int(Range.linear(1, 100)).log("n")
} yield withIO { implicit ticker =>
// Your test
val exected = ??? // A
val actual = ??? // IO[A]
actual.completeThen(_ ==== expected)
}

completeThen

Use extras.hedgehog.ce3.syntax.runner and completeThen instead of unsafeRunSync().

import cats.effect._

import extras.hedgehog.ce3.syntax.runner._

import hedgehog._
import hedgehog.runner._

object SomeSpec extends Properties {

override def tests: List[Test] = List(
property("test with CatsEffectRunner and completeThen", testCatsEffectRunnerWithCompleteThen)
)

def testCatsEffectRunnerWithCompleteThen: Property = for {
n <- Gen.int(Range.linear(Int.MinValue, Int.MaxValue)).log("n")
} yield withIO { implicit ticker =>

val expected = n
val actual = IO(n)

actual.completeThen { actual =>
actual ==== expected
}
}
}

errorThen

If you want to test with IO which may result in some Exception thrown, you can use errorThen instead of unsafeRunSync() and Try.

import cats.effect._

import extras.hedgehog.ce3.syntax.runner._

import hedgehog._
import hedgehog.runner._

object SomeSpec extends Properties {

override def tests: List[Test] = List(
property("test with CatsEffectRunner and errorThen", testCatsEffectRunnerWithErrorThen)
)

def testCatsEffectRunnerWithErrorThen: Property = for {
message <- Gen.string(Gen.alphaNum, Range.linear(1, 10)).log("message")
error <- Gen
.element1(
TestError.someTestError(s"Don't worry it's only a test error. $message"),
TestError.anotherTestError(s"Don't worry it's only a test error. $message")
)
.log("error")
} yield withIO { implicit ticker =>

val expected = error
val actual = IO.raiseError[Int](error)

actual.errorThen { actual =>
actual ==== expected
}
}

sealed abstract class TestError(val message: String) extends RuntimeException(message)

object TestError {
final case class SomeTestError(override val message: String) extends TestError(message)
final case class AnotherTestError(override val message: String) extends TestError(message)

def anotherTestError(message: String): TestError = AnotherTestError(message)
def someTestError(message: String): TestError = SomeTestError(message)

}
}