Improve intercalate tests after review

typelevel · Jan 6, 2017 · 755f9e9 · 755f9e9
1 parent b859ea3
commit 755f9e9
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Showing 4 changed files with 17 additions and 7 deletions.
diff --git a/core/src/main/scala/cats/Foldable.scala b/core/src/main/scala/cats/Foldable.scala
@@ -393,8 +393,12 @@ import simulacrum.typeclass
    * scala> import cats.implicits._
    * scala> Foldable[List].intercalate(List("a","b","c"), "-")
    * res0: String = a-b-c
+   * scala> Foldable[List].intercalate(List("a"), "-")
+   * res1: String = a
+   * scala> Foldable[List].intercalate(List.empty[String], "-")
+   * res2: String = ""
    * scala> Foldable[Vector].intercalate(Vector(1,2,3), 1)
-   * res1: Int = 8
+   * res3: Int = 8
    * }}}
    */
   def intercalate[A](fa: F[A], a: A)(implicit A: Monoid[A]): A =

diff --git a/core/src/main/scala/cats/Reducible.scala b/core/src/main/scala/cats/Reducible.scala
@@ -166,6 +166,8 @@ import simulacrum.typeclass
    * scala> val nel = NonEmptyList.of("a", "b", "c")
    * scala> Reducible[NonEmptyList].intercalate1(nel, "-")
    * res0: String = a-b-c
+   * scala> Reducible[NonEmtpyList].intercalate1(NonEmptyList.of("a"), "-")
+   * res1: String = a
    * }}}
    */
   def intercalate1[A](fa: F[A], a: A)(implicit A: Semigroup[A]): A =

diff --git a/tests/src/test/scala/cats/tests/FoldableTests.scala b/tests/src/test/scala/cats/tests/FoldableTests.scala
@@ -6,7 +6,7 @@ import org.scalacheck.Arbitrary
 
 import cats.instances.all._
 
-abstract class FoldableCheck[F[_]: Foldable](name: String)(implicit ArbFInt: Arbitrary[F[Int]]) extends CatsSuite with PropertyChecks {
+abstract class FoldableCheck[F[_]: Foldable](name: String)(implicit ArbFInt: Arbitrary[F[Int]], ArbFString: Arbitrary[F[String]]) extends CatsSuite with PropertyChecks {
 
   def iterator[T](fa: F[T]): Iterator[T]
 
@@ -69,10 +69,8 @@ abstract class FoldableCheck[F[_]: Foldable](name: String)(implicit ArbFInt: Arb
   }
 
   test("intercalate") {
-    forAll { (fa: F[Int], a: Int) =>
-      val list = fa.toList
-      val sum = list.sum + (math.max(list.length - 1, 0) * a)
-      fa.intercalate(a) should === (sum)
+    forAll { (fa: F[String], a: String) =>
+      fa.intercalate(a) should === (fa.toList.mkString(a))
     }
   }
 }

diff --git a/tests/src/test/scala/cats/tests/ReducibleTests.scala b/tests/src/test/scala/cats/tests/ReducibleTests.scala
@@ -62,7 +62,7 @@ class ReducibleTestsAdditional extends CatsSuite {
 
 }
 
-abstract class ReducibleCheck[F[_]: Reducible](name: String)(implicit ArbFInt: Arbitrary[F[Int]]) extends FoldableCheck[F](name) {
+abstract class ReducibleCheck[F[_]: Reducible](name: String)(implicit ArbFInt: Arbitrary[F[Int]], ArbFString: Arbitrary[F[String]]) extends FoldableCheck[F](name) {
   def range(start: Long, endInclusive: Long): F[Long]
 
   test(s"Reducible[$name].reduceLeftM stack safety") {
@@ -80,4 +80,10 @@ abstract class ReducibleCheck[F[_]: Reducible](name: String)(implicit ArbFInt: A
       fa.toList.toNel should === (Some(fa.toNonEmptyList))
     }
   }
+
+  test(s"Reducible[$name].intercalate1") {
+    forAll { (fa: F[String], a: String) =>
+      fa.intercalate1(a) === (fa.toList.mkString(a))
+    }
+  }
 }