Add missing test for traverseEitherMerged

Author: klimick

tests/Runtime/Functions/Collection/EitherTraverseTest.php

@@ -13,6 +13,7 @@
 use function Fp\Collection\traverseEither;
 use function Fp\Collection\traverseEitherAcc;
 use function Fp\Collection\traverseEitherKV;
+use function Fp\Collection\traverseEitherMerged;
 
 final class EitherTraverseTest extends TestCase
 {
@@ -36,6 +37,26 @@ public function testTraverse(): void
         );
     }
 
+    public function testTraverseEitherMerged(): void
+    {
+        /** @psalm-var list<int> $c */
+        $c = [1, 2, 3, 4];
+
+        $this->assertEquals(
+            Either::right($c),
+            traverseEitherMerged($c, fn(int $v) => $v < 5
+                ? Either::right($v)
+                : Either::left(["{$v} is too high"]))
+        );
+
+        $this->assertEquals(
+            Either::left(['3 is too high', '4 is too high']),
+            traverseEitherMerged($c, fn(int $v) => $v < 3
+                ? Either::right($v)
+                : Either::left(["{$v} is too high"]))
+        );
+    }
+
     public function testTraverseAcc(): void
     {
         /** @psalm-var list<int> $c */