diff --git a/test/MergeTest.php b/test/MergeTest.php
index 29eafb3..962897b 100644
--- a/test/MergeTest.php
+++ b/test/MergeTest.php
@@ -21,21 +21,42 @@ public function getArrays(): array
 
     /**
      * @dataProvider getArrays
-     *
-     * @param array $array
-     * @param array $expected
      */
     public function testMerge(array $array, array $expected): void
     {
-        $pipelines = \array_map(static function (array $iterator): Pipeline {
-            return Pipeline::fromIterable($iterator)->tap(fn () => delay(0.01));
-        }, $array);
+        $pipelines = \array_map(
+            fn (array $iterator) => Pipeline::fromIterable($iterator)
+                ->tap(fn () => delay(0.01)),
+            $array,
+        );
 
         $pipeline = Pipeline::merge($pipelines);
 
         self::assertSame($expected, $pipeline->toArray());
     }
 
+    /**
+     * @dataProvider getArrays
+     * @depends      testMerge
+     */
+    public function testMergeWithConcurrentMap(array $array, array $expected): void
+    {
+        $mapper = static fn (int $value) => $value * 10;
+
+        $pipelines = \array_map(
+            fn (array $iterator) => Pipeline::fromIterable($iterator)
+                ->tap(fn () => delay(0.01))
+                ->concurrent(3)
+                ->ordered()
+                ->map($mapper),
+            $array,
+        );
+
+        $pipeline = Pipeline::merge($pipelines);
+
+        self::assertSame(\array_map($mapper, $expected), $pipeline->toArray());
+    }
+
     /**
      * @depends testMerge
      */
@@ -44,7 +65,6 @@ public function testMergeWithDelayedYields(): void
         $pipelines = [];
         $values1 = [$this->asyncValue(0.01, 1), $this->asyncValue(0.05, 2), $this->asyncValue(0.07, 3)];
         $values2 = [$this->asyncValue(0.02, 4), $this->asyncValue(0.04, 5), $this->asyncValue(0.06, 6)];
-        $expected = [1, 4, 5, 2, 6, 3];
 
         $pipelines[] = Pipeline::fromIterable(function () use ($values1) {
             foreach ($values1 as $value) {
@@ -60,7 +80,7 @@ public function testMergeWithDelayedYields(): void
 
         $pipeline = Pipeline::merge($pipelines);
 
-        self::assertSame($expected, $pipeline->toArray());
+        self::assertSame([1, 4, 5, 2, 6, 3], $pipeline->toArray());
     }
 
     /**
@@ -90,8 +110,8 @@ public function testDisposedMerge(): void
      */
     public function testMergeWithFailedPipeline(): void
     {
-        $exception = new TestException;
-        $generator = Pipeline::fromIterable(static function () use ($exception) {
+        $exception = new TestException();
+        $generator = Pipeline::fromIterable(function () use ($exception) {
             yield 1; // Emit once before failing.
             throw $exception;
         });