Correction + test Collection::prependCollection

src/Collections/Collection.php

@@ -48,12 +48,15 @@ class Collection extends ImmutableCollection implements ICollection {
      * @inheritDoc
      */
     public function prependCollection (IImmutableCollection ...$collections): ICollection {
-        foreach ($collections as $collection) {
+        $prepend = array_merge(
-            foreach ($collection as $value) {
+            ...array_map(
-                $this->prepend($value);
+                   function (IImmutableCollection $collection): array {
-            }
+                       return $collection->values()->toArray();
-        }
+                   },
-        return $this;
+                   $collections
+               )
+        );
+        return $this->prepend(...$prepend);
     }
 
     /**

tests/test_class.php

@@ -23,9 +23,12 @@ class Measure {
  * @return Collection<int, Measure>
  */
 function getMeasures (): Collection {
+    $mesures_avant = new Collection();
+    $mesures_avant->add(new Measure(38), new Measure(29));
+
     $measures = new Collection();
     $measures->add(new Measure(27), new Measure(34));
-    $measures->prepend(new Measure(38));
+    $measures->prependCollection($mesures_avant);
 
     return $measures;
 }