Merge pull request #83 from Yaskier/patch-1

Concatenate and add elements examples for Lists.scala

Author: juanpedromoreno

src/main/scala/stdlib/Lists.scala

@@ -160,6 +160,24 @@ object Lists extends FlatSpec with Matchers with org.scalaexercises.definitions.
     a should be(res0)
   }
 
+  /** You can prepend elements to a List to get a new List:
+   */
+  def addElementsLists(res0: List[Int]) {
+    val a = List(1, 3, 5, 7)
+
+    0 :: a should be(res0)
+  }
+
+  /** Lists can be concatened and Nil is an empty List:
+   */
+  def concatenateLists(res0: List[Int], res1: List[Int]) {
+    val head = List(1, 3)
+    val tail = List(5, 7)
+
+    head ::: tail should be(res0)
+    head ::: Nil should be(res1)
+  }
+
   /** Lists reuse their tails:
    */
   def reuseTailsLists(
@@ -179,5 +197,4 @@ object Lists extends FlatSpec with Matchers with org.scalaexercises.definitions.
     b.tail should be(res4)
     c.tail should be(res5)
   }
-
 }

src/test/scala/stdlib/ListsSpec.scala

@@ -129,6 +129,24 @@ class ListsSpec extends Spec with Checkers {
     )
   }
 
+  def `add elements` = {
+    check(
+      Test.testSuccess(
+        Lists.addElementsLists _,
+        List(0, 1, 3, 5, 7) :: HNil
+      )
+    )
+  }
+
+  def `concatenate lists` = {
+    check(
+      Test.testSuccess(
+        Lists.concatenateLists _,
+        List(1, 3, 5, 7) :: List(1, 3) :: HNil
+      )
+    )
+  }
+
   def `lists share tails` = {
     check(
       Test.testSuccess(