improve the type specificity of the syntax extensions; implement test…

… for .toNes
gerlichlab · Oct 28, 2024 · 79e6828 · 79e6828
1 parent 8e8fbda
commit 79e6828
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Showing 2 changed files with 25 additions and 12 deletions.
diff --git a/modules/pan/src/main/scala/collections.scala b/modules/pan/src/main/scala/collections.scala
@@ -1,5 +1,6 @@
 package at.ac.oeaw.imba.gerlich.gerlib
 
+import scala.collection.immutable.SortedSet
 import cats.*
 import cats.data.{NonEmptyList, NonEmptySet}
 import io.github.iltotore.iron.{:|, Constraint, refineEither, refineUnsafe}
@@ -95,10 +96,20 @@ object collections:
         infix def +(x: X): AtLeast2Set[X] =
           (xs + x).refineUnsafe[MinLength[2]]
 
+        /** With knowledge that the given container type is an set, we can use the underlying
+          * collection's {@code .contains} member.
+          *
+          * @return
+          *   Whether the underlying collection contains the given element
+          */
+        def contains(x: X): Boolean = (xs: Set[X]).contains(x)
+
         /** Convert safely to [[cats.data.NonEmptySet]]. */
         def toNes(using ord: Order[X]): NonEmptySet[X] =
-          val sorted = scala.collection.immutable.SortedSet.from(xs)(ord.toOrdering)
-          NonEmptySet.fromSetUnsafe(sorted)
+          NonEmptySet.fromSetUnsafe(xs.toSortedSet)
+
+        def toSortedSet(using ord: Order[X]): SortedSet[X] =
+          SortedSet.from(xs)(ord.toOrdering)
 
       extension [X](xs: AtLeast2List[X])
         /** With knowledge that the given container type is an set, we can use the underlying
@@ -115,15 +126,6 @@ object collections:
         /** We can safely convert to [[cats.data.NonEmptyList]]. */
         def toNel: NonEmptyList[X] = NonEmptyList(xs.head, xs.tail)
 
-      extension [C[*] <: Set[*], X](xs: AtLeast2[C, X])
-        /** With knowledge that the given container type is an set, we can use the underlying
-          * collection's {@code .contains} member.
-          *
-          * @return
-          *   Whether the underlying collection contains the given element
-          */
-        def contains(x: X): Boolean = (xs: C[X]).contains(x)
-
       extension [C[*], X](xs: AtLeast2[C, X])
         /** When the underlying container type has a functor, use it to {@code .map} over the
           * refined collection.

diff --git a/modules/pan/src/test/scala/TestAtLeast2.scala b/modules/pan/src/test/scala/TestAtLeast2.scala
@@ -87,6 +87,17 @@ class TestAtLeast2
   checkAll("AtLeast2[Set, *].SemigroupLaws", SemigroupKTests[AtLeast2Set].semigroupK[Int])
 
   test("When syntax is imported, AtLeast2[Set, A] may be represented as cats.data.NonEmptySet[A]."):
-    pending
+    assertCompiles("AtLeast2.unsafe(Set(1, 2))") // Precondition: we can build the collection.
+    assertTypeError(
+      "AtLeast2.unsafe(Set(1, 2)).toNes"
+    ) // Test: without syntax import, .toNes is unavailable.
+    assertCompiles(
+      "import AtLeast2.syntax.toNes; AtLeast2.unsafe(Set(1, 2)).toNes"
+    ) // Test: with syntax import, .toNes becomes available.
+
+    // Check the equivalence of the result of the .toNes operation and the underlying collection.
+    import AtLeast2.syntax.{toNes, toSortedSet}
+    forAll: (xs: AtLeast2[Set, Int]) =>
+      xs.toNes shouldEqual NonEmptySet.fromSetUnsafe(xs.toSortedSet)
 
 end TestAtLeast2