Merge pull request #722 from ceedubs/streamingt-tostring

Make StreamingT toString more like Streaming toString
typelevel · Dec 7, 2015 · b8be77b · b8be77b
2 parents 492b030 + b6736ba
commit b8be77b
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Showing 2 changed files with 13 additions and 4 deletions.
diff --git a/core/src/main/scala/cats/data/StreamingT.scala b/core/src/main/scala/cats/data/StreamingT.scala
@@ -273,11 +273,12 @@ sealed abstract class StreamingT[F[_], A] extends Product with Serializable { lh
    * This method will not force evaluation of any lazy part of a
    * stream. As a result, you will see at most one element (the first
    * one).
-   *
-   * Use .toString(n) to see the first n elements of the stream.
    */
-  override def toString: String =
-    "StreamingT(...)"
+  override def toString: String = this match {
+    case Cons(a, _) => s"StreamingT($a, ...)"
+    case Wait(_) => "StreamingT(...)"
+    case Empty() => "StreamingT()"
+  }
 }
 
 object StreamingT extends StreamingTInstances {

diff --git a/tests/src/test/scala/cats/tests/StreamingTTests.scala b/tests/src/test/scala/cats/tests/StreamingTTests.scala
@@ -176,6 +176,14 @@ class StreamingTTests extends CatsSuite {
       StreamingT[Id, Int](x1, x2, tail: _*) should === (fromList)
     }
   }
+
+  test("toString is wrapped in StreamingT()"){
+    forAll { (xs: StreamingT[Option, Int]) =>
+      val s = xs.toString
+      s.take(11) should === ("StreamingT(")
+      s.last should === (')')
+    }
+  }
 }
 
 class SpecificStreamingTTests extends CatsSuite {