EphemeralStream#zip crashed on unequal lengths; fix & test.

scalaz · Aug 23, 2013 · ab4e4b6 · ab4e4b6
1 parent 07fea2e
commit ab4e4b6
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diff --git a/core/src/main/scala/scalaz/EphemeralStream.scala b/core/src/main/scala/scalaz/EphemeralStream.scala
@@ -75,7 +75,7 @@ sealed abstract class EphemeralStream[A] {
   }
 
   def zip[B](b: => EphemeralStream[B]): EphemeralStream[(A, B)] =
-    if(isEmpty && b.isEmpty)
+    if(isEmpty || b.isEmpty)
       emptyEphemeralStream
     else
       cons((head(), b.head()), tail() zip b.tail())

diff --git a/tests/src/test/scala/scalaz/EphemeralStreamTest.scala b/tests/src/test/scala/scalaz/EphemeralStreamTest.scala
@@ -28,4 +28,12 @@ class EphemeralStreamTest extends Spec {
   "foldLeft" ! prop{ xs: List[List[Int]] =>
     Foldable[EphemeralStream].foldLeft(EphemeralStream(xs: _*), List[Int]())(_ ::: _) must be_===(xs.foldLeft(List[Int]())(_ ::: _))
   }
+
+  "zip has right length" ! prop {(xs: EphemeralStream[Int], ys: EphemeralStream[Int]) =>
+    (xs zip ys).length must be_===(xs.length min ys.length)
+  }
+
+  "interleave has right length" ! prop {(xs: EphemeralStream[Int], ys: EphemeralStream[Int]) =>
+    (xs interleave ys).length must be_===(xs.length + ys.length)
+  }
 }