Create Checkers.Helpers helper functions.

Author: zainab-ali

modules/scalacheck/shared/src/main/scala/weaver/scalacheck/CheckConfig.scala

@@ -28,15 +28,21 @@ case class CheckConfig private (
   /**
    * The proportion of values discarded by the generator allowed before the test
    * is considered failed.
+   *
+   * A value is considered discarded if the generator outputs [[None]]. The
+   * generator must not discard more values than the number of successful runs,
+   * so this ratio is a proportion of [[minimumSuccessful]].
    */
   def withMaximumDiscardRatio(maximumDiscardRatio: Int) = copy(
     maximumDiscardRatio = maximumDiscardRatio
   )
 
+  /** The [[scalacheck.Gen.Parameters.size]] of the generator. */
   def withMaximumGeneratorSize(maximumGeneratorSize: Int) = copy(
     maximumGeneratorSize = maximumGeneratorSize
   )
 
+  /** The number of concurrent runs. */
   def withPerPropertyParallelism(perPropertyParallelism: Int) = copy(
     perPropertyParallelism = perPropertyParallelism
   )

modules/scalacheck/shared/src/main/scala/weaver/scalacheck/Checkers.scala

@@ -7,6 +7,8 @@ import scala.util.control.NoStackTrace
 import org.scalacheck.rng.Seed
 import org.scalacheck.{ Arbitrary, Gen }
 import cats.data.Validated
+import cats.effect.Concurrent
+import cats.MonadThrow
 
 trait Checkers {
   self: EffectSuiteAux =>
@@ -20,7 +22,7 @@ trait Checkers {
     f andThen (b => Prop[F, B].lift(b))
   }
 
-  // Configuration for property-based tests
+  /** Configuration for all property-based tests in this suite. */
   def checkConfig: CheckConfig = CheckConfig.default
 
   class PartiallyAppliedForall(config: CheckConfig) {
@@ -43,9 +45,6 @@ trait Checkers {
         B: PropF](
         f: (A1, A2, A3) => B)(
         implicit loc: SourceLocation): F[Expectations] = {
-      implicit val tuple3Show: Show[(A1, A2, A3)] = {
-        case (a1, a2, a3) => s"(${a1.show},${a2.show},${a3.show})"
-      }
       forall(implicitly[Arbitrary[(A1, A2, A3)]].arbitrary)(liftProp(
         f.tupled))
     }
@@ -58,10 +57,6 @@ trait Checkers {
         B: PropF
     ](f: (A1, A2, A3, A4) => B)(
         implicit loc: SourceLocation): F[Expectations] = {
-      implicit val tuple3Show: Show[(A1, A2, A3, A4)] = {
-        case (a1, a2, a3, a4) =>
-          s"(${a1.show},${a2.show},${a3.show},${a4.show})"
-      }
       forall(implicitly[Arbitrary[(A1, A2, A3, A4)]].arbitrary)(
         liftProp(f.tupled))
     }
@@ -75,10 +70,6 @@ trait Checkers {
         B: PropF
     ](f: (A1, A2, A3, A4, A5) => B)(
         implicit loc: SourceLocation): F[Expectations] = {
-      implicit val tuple3Show: Show[(A1, A2, A3, A4, A5)] = {
-        case (a1, a2, a3, a4, a5) =>
-          s"(${a1.show},${a2.show},${a3.show},${a4.show},${a5.show})"
-      }
       forall(implicitly[Arbitrary[(A1, A2, A3, A4, A5)]].arbitrary)(
         liftProp(f.tupled))
     }
@@ -93,10 +84,6 @@ trait Checkers {
         B: PropF
     ](f: (A1, A2, A3, A4, A5, A6) => B)(
         implicit loc: SourceLocation): F[Expectations] = {
-      implicit val tuple3Show: Show[(A1, A2, A3, A4, A5, A6)] = {
-        case (a1, a2, a3, a4, a5, a6) =>
-          s"(${a1.show},${a2.show},${a3.show},${a4.show},${a5.show},${a6.show})"
-      }
       forall(implicitly[Arbitrary[(A1, A2, A3, A4, A5, A6)]].arbitrary)(
         liftProp(f.tupled))
     }
@@ -106,6 +93,59 @@ trait Checkers {
       forall_(gen, liftProp(f))
 
     private def forall_[A: Show](gen: Gen[A], f: A => F[Expectations])(
+        implicit loc: SourceLocation): F[Expectations] =
+      Helpers.forall(config, gen, f)
+  }
+
+  object forall extends PartiallyAppliedForall(checkConfig) {
+
+    /** Configuration for this specific property assertion. */
+    def withConfig(config: CheckConfig) = new PartiallyAppliedForall(config)
+  }
+}
+
+object Checkers {
+  // These allow us to define functions that go from F[Expectations]
+  trait Prop[F[_], A] {
+    def lift(a: A): F[Expectations]
+  }
+
+  object Prop {
+    def apply[F[_], B](implicit ev: Prop[F, B]): Prop[F, B] = ev
+
+    implicit def wrap[F[_]: Applicative]: Prop[F, Expectations] =
+      new Prop[F, Expectations] {
+        def lift(a: Expectations): F[Expectations] = Applicative[F].pure(a)
+      }
+
+    implicit def unwrapped[F[_], FE](
+        implicit ev: FE <:< F[Expectations]): Prop[F, FE] =
+      new Prop[F, FE] {
+        def lift(a: FE): F[Expectations] = ev(a)
+      }
+  }
+
+  private def failureMessage(ith: Int, seed: Seed, input: String): String =
+    s"""Property test failed on try $ith with seed ${seed} and input $input.
+                |You can reproduce this by adding the following override to your suite:
+                |
+                |override def checkConfig = super.checkConfig.withInitialSeed($seed.toOption)""".stripMargin
+
+  private[scalacheck] class PropertyTestError(
+      ith: Int,
+      seed: Seed,
+      input: String,
+      cause: Throwable)
+      extends RuntimeException(failureMessage(ith, seed, input), cause)
+      with NoStackTrace
+
+  object Helpers {
+
+    /** Runs assertions in a property test concurrently. */
+    def forall[F[_]: Defer: Concurrent, A: Show](
+        config: CheckConfig,
+        gen: Gen[A],
+        f: A => F[Expectations])(
         implicit loc: SourceLocation): F[Expectations] = {
       val params = Gen.Parameters.default.withNoInitialSeed.withSize(
         config.maximumGeneratorSize)
@@ -130,37 +170,33 @@ trait Checkers {
         .map { status => status.endResult(config) }
     }
 
-    private def seedStream(initial: Seed): fs2.Stream[F, Seed] =
-      fs2.Stream.iterate[F, Seed](initial)(_.slide)
-  }
-
-  object forall extends PartiallyAppliedForall(checkConfig) {
-    def withConfig(config: CheckConfig) = new PartiallyAppliedForall(config)
-  }
-
-  private def testOne[T: Show](
-      gen: Gen[T],
-      f: T => F[Expectations])(
-      params: Gen.Parameters,
-      seed: Seed): F[TestResult] = {
-    Defer[F](self.effect).defer {
-      gen(params, seed)
-        .traverse(x => f(x).attempt.map(x -> _))
-        .map { (x: Option[(T, Either[Throwable, Expectations])]) =>
-          x match {
-            case Some((_, Right(ex))) if ex.run.isValid => TestResult.Success
-            case Some((t, Right(ex))) => TestResult.Failure(t.show, ex)
-            case Some((t, Left(exception: ExpectationFailed))) =>
-              TestResult.Failure(t.show,
-                                 Expectations(Validated.invalidNel(exception)))
-            case Some((t, Left(other))) => TestResult.Exception(t.show, other)
-            case None                   => TestResult.Discard
+    private def testOne[F[_]: Defer: MonadThrow, T: Show](
+        gen: Gen[T],
+        f: T => F[Expectations])(
+        params: Gen.Parameters,
+        seed: Seed): F[TestResult] = {
+      Defer[F].defer {
+        gen(params, seed)
+          .traverse(x => f(x).attempt.map(x -> _))
+          .map { (x: Option[(T, Either[Throwable, Expectations])]) =>
+            x match {
+              case Some((_, Right(ex))) if ex.run.isValid => TestResult.Success
+              case Some((t, Right(ex))) => TestResult.Failure(t.show, ex)
+              case Some((t, Left(exception: ExpectationFailed))) =>
+                TestResult.Failure(
+                  t.show,
+                  Expectations(Validated.invalidNel(exception)))
+              case Some((t, Left(other))) => TestResult.Exception(t.show, other)
+              case None                   => TestResult.Discard
+            }
           }
-        }
+      }
     }
-  }
 
-  private[scalacheck] case class Status[T](
+    private def seedStream[F[_]](initial: Seed): fs2.Stream[F, Seed] =
+      fs2.Stream.iterate[F, Seed](initial)(_.slide)
+  }
+  private case class Status[T](
       succeeded: Int,
       discarded: Int,
       failure: Option[Expectations]
@@ -198,28 +234,6 @@ trait Checkers {
     def start[T] = Status[T](0, 0, None)
   }
 
-}
-
-object Checkers {
-  trait Prop[F[_], A] {
-    def lift(a: A): F[Expectations]
-  }
-
-  object Prop {
-    def apply[F[_], B](implicit ev: Prop[F, B]): Prop[F, B] = ev
-
-    implicit def wrap[F[_]: Applicative]: Prop[F, Expectations] =
-      new Prop[F, Expectations] {
-        def lift(a: Expectations): F[Expectations] = Applicative[F].pure(a)
-      }
-
-    implicit def unwrapped[F[_], FE](
-        implicit ev: FE <:< F[Expectations]): Prop[F, FE] =
-      new Prop[F, FE] {
-        def lift(a: FE): F[Expectations] = ev(a)
-      }
-  }
-
   private sealed trait TestResult
   private object TestResult {
     case object Success extends TestResult
@@ -229,17 +243,4 @@ object Checkers {
     case class Exception(input: String, error: Throwable) extends TestResult
   }
 
-  private def failureMessage(ith: Int, seed: Seed, input: String): String =
-    s"""Property test failed on try $ith with seed ${seed} and input $input.
-                |You can reproduce this by adding the following override to your suite:
-                |
-                |override def checkConfig = super.checkConfig.withInitialSeed($seed.toOption)""".stripMargin
-
-  private class PropertyTestError(
-      ith: Int,
-      seed: Seed,
-      input: String,
-      cause: Throwable)
-      extends RuntimeException(failureMessage(ith, seed, input), cause)
-      with NoStackTrace
 }