Merge pull request #20 from rallyhealth/gen-collect

Add Gen.collect operation

Author: jeffmay

README.md

@@ -1,8 +1,8 @@
-<a href='https://travis-ci.org/gloriousfutureio/scalacheck-ops'>
-  <img src='https://travis-ci.org/gloriousfutureio/scalacheck-ops.svg?branch=master' alt='Build Status' />
+<a href='https://travis-ci.org/rallyhealth/scalacheck-ops'>
+  <img src='https://travis-ci.org/rallyhealth/scalacheck-ops.svg?branch=master' alt='Build Status' />
 </a>
-<a href='https://coveralls.io/github/gloriousfutureio/scalacheck-ops?branch=master'>
-  <img src='https://coveralls.io/repos/github/gloriousfutureio/scalacheck-ops/badge.svg?branch=master' alt='Coverage Status' />
+<a href='https://coveralls.io/github/rallyhealth/scalacheck-ops?branch=master'>
+  <img src='https://coveralls.io/repos/github/rallyhealth/scalacheck-ops/badge.svg?branch=master' alt='Coverage Status' />
 </a>
 <table>
   <tr>
@@ -19,17 +19,17 @@
     </td>
     <td>
       <a href='https://bintray.com/jeffmay/maven/scalacheck-ops_1-12/_latestVersion'>
-        <img src='https://api.bintray.com/packages/jeffmay/maven/scalacheck-ops_1-12/images/download.svg'>
+        <img src='https://api.bintray.com/packages/rallyhealth/ivy-scala-libs/scalacheck-ops_1-12/images/download.svg'>
       </a>
     </td>
     <td>
       <a href='https://bintray.com/jeffmay/maven/scalacheck-ops_1-13/_latestVersion'>
-        <img src='https://api.bintray.com/packages/jeffmay/maven/scalacheck-ops_1-13/images/download.svg'>
+        <img src='https://api.bintray.com/packages/rallyhealth/ivy-scala-libs/scalacheck-ops_1-13/images/download.svg'>
       </a>
     </td>
     <td>
       <a href='https://bintray.com/jeffmay/maven/scalacheck-ops_1-14/_latestVersion'>
-        <img src='https://api.bintray.com/packages/jeffmay/maven/scalacheck-ops_1-14/images/download.svg'>
+        <img src='https://api.bintray.com/packages/rallyhealth/ivy-scala-libs/scalacheck-ops_1-14/images/download.svg'>
       </a>
     </td>
   </tr>
@@ -50,6 +50,9 @@ with scalacheck-ops.
 
 ### Compatibility
 
+**NOTE** Version 1.x lives under the `"me.jeffmay"` organization. Version 2.x lives
+under `"com.rallyhealth"`
+
 **NOTE** Version 2.x and above **requires** JDK >=8 and Scala >=2.11 as this 
 library expects the java.time standard library module.
 

build.sbt

@@ -8,13 +8,17 @@ publishLocal := {}
 organization in ThisBuild := "com.rallyhealth"
 organizationName in ThisBuild := "Rally Health"
 
-semVerLimit in ThisBuild := "2.0.999"
+semVerLimit in ThisBuild := "2.1.999"
 scalaVersion in ThisBuild := "2.11.11"
 licenses in ThisBuild := Seq("MIT" -> url("http://opensource.org/licenses/MIT"))
 
-bintrayOrganization in ThisBuild := Some("rallyhealth")
+val bintrayOrg = "rallyhealth"
+
+bintrayOrganization := Some(bintrayOrg)
 bintrayRepository := "ivy-scala-libs"
 
+resolvers in ThisBuild += Resolver.bintrayRepo(bintrayOrg, bintrayRepository.value)
+
 def commonProject(id: String, artifact: String, path: String): Project = {
   Project(id, file(path)).settings(
     name := artifact,

core/src/main/scala/org/scalacheck/ops/GenOps.scala

@@ -13,6 +13,13 @@ object GenOps {
   def bits(size: Int): Gen[BitSet] = Gen.listOfN(size, binary).map(BitSet(_: _*))
   def bits: Gen[BitSet] = Gen.sized(bits)
 
+  def collect[T, U](gen: Gen[T], retryUntilMatch: Boolean = false)(pf: PartialFunction[T, U]): Gen[U] = {
+    {
+      if (retryUntilMatch) gen.retryUntil(pf.isDefinedAt)
+      else gen.suchThat(pf.isDefinedAt)
+    } map pf
+  }
+
   def enumValue[E <: Enumeration](enum: E): Gen[enum.Value] =
     Gen.oneOf[enum.Value](enum.values.toSeq)
 

core/src/test/scala/org/scalacheck/ops/GenOpsSpec.scala

@@ -19,6 +19,35 @@ with ScalaCheckImplicits {
     }
   }
 
+  behavior of "Gen.collect"
+
+  it should "use suchThat when retryUntilMatch is false" in {
+    val collectEven = Gen.collect(Gen.chooseNum(1, 10), retryUntilMatch = false) {
+      case x if x % 2 == 0 => x
+    }
+    val examples = collectEven.sampleIterator.take(100).toSeq
+    examples should contain (None)
+    assert(examples forall (_ forall (_ % 2 == 0)))
+  }
+
+  it should "use retryUntil when retryUntilMatch is true" in {
+    val collectEven = Gen.collect(Gen.chooseNum(1, 10), retryUntilMatch = true) {
+      case x if x % 2 == 0 => x
+    }
+    val examples = collectEven.sampleIterator.take(100).toSeq
+    examples should not contain None
+    assert(examples forall (_ exists (_ % 2 == 0)))
+  }
+
+  it should "avoid infinite recursion by default" in {
+    val collectNegative = Gen.collect(Gen.chooseNum(1, 10)) {
+      case x if x < 0 => x
+    }
+    an [EmptyGenSampleException[Int]] shouldBe thrownBy {
+      collectNegative.getOrThrow
+    }
+  }
+
   behavior of "Gen.setOfN"
 
   it should "be able to generate a certain size" in {