Merge pull request #380 from ashawley/double-infinity

Fix Gen.choose for Double infinity

Author: rickynils

jvm/src/test/scala/org/scalacheck/GenSpecification.scala

@@ -103,7 +103,20 @@ object GenSpecification extends Properties("Gen") {
 
   import Double.{MinValue, MaxValue}
   property("choose-large-double") = forAll(choose(MinValue, MaxValue)) { x =>
-    MinValue <= x && x <= MaxValue
+    MinValue <= x && x <= MaxValue && !x.isNaN
+  }
+
+  import Double.{NegativeInfinity, PositiveInfinity}
+  property("choose-infinite-double") = {
+    forAll(Gen.choose(NegativeInfinity, PositiveInfinity)) { x =>
+      NegativeInfinity <= x && x <= PositiveInfinity && !x.isNaN
+    }
+  }
+
+  property("choose-infinite-double-fix-zero-defect-379") = {
+    Prop.forAllNoShrink(listOfN(3, choose(NegativeInfinity, PositiveInfinity))) { xs =>
+      xs.exists(_ != 0d)
+    }
   }
 
   property("choose-xmap") = {

src/main/scala/org/scalacheck/Gen.scala

@@ -399,6 +399,12 @@ object Gen extends GenArities{
       new Choose[Double] {
         def choose(low: Double, high: Double) =
           if (low > high) throw new IllegalBoundsError(low, high)
+          else if (low == Double.NegativeInfinity)
+            frequency(1 -> const(Double.NegativeInfinity),
+                      9 -> choose(Double.MinValue, high))
+          else if (high == Double.PositiveInfinity)
+            frequency(1 -> const(Double.PositiveInfinity),
+                      9 -> choose(low, Double.MaxValue))
           else gen(chDbl(low,high))
       }