From 03431a215576a5ecb9e6dee66aa06bb84f98b3ce Mon Sep 17 00:00:00 2001
From: Oliver Vogel <oliver@olivervogel.com>
Date: Fri, 11 Feb 2022 19:54:13 +0100
Subject: [PATCH] Fixed bug in ModifierStack, Added tests for apply method

---
 src/ModifierStack.php      |  2 ++
 tests/ModiferStackTest.php | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/ModifierStack.php b/src/ModifierStack.php
index 13eac80a..109fbfc9 100644
--- a/src/ModifierStack.php
+++ b/src/ModifierStack.php
@@ -17,6 +17,8 @@ class ModifierStack implements ModifierInterface
         foreach ($this->modifiers as $modifier) {
             $modifier->apply($image);
         }
+
+        return $image;
     }
 
     public function push(ModifierInterface $modifier): self
diff --git a/tests/ModiferStackTest.php b/tests/ModiferStackTest.php
index 8577d3c1..afe99234 100644
--- a/tests/ModiferStackTest.php
+++ b/tests/ModiferStackTest.php
@@ -3,7 +3,9 @@
 namespace Intervention\Image\Tests;
 
 use Intervention\Image\Drivers\Gd\Modifiers\GreyscaleModifier;
+use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\ModifierStack;
+use Mockery;
 
 /**
  * @covers \Intervention\Image\ModifierStack
@@ -22,4 +24,19 @@ class ModifierStackTest extends TestCase
         $result = $stack->push(new GreyscaleModifier());
         $this->assertInstanceOf(ModifierStack::class, $result);
     }
+
+    public function testApply(): void
+    {
+        $image = Mockery::mock(ImageInterface::class);
+
+        $modifier1 = Mockery::mock(AbstractColor::class)->makePartial();
+        $modifier1->shouldReceive('apply')->once()->with($image);
+
+        $modifier2 = Mockery::mock(AbstractColor::class)->makePartial();
+        $modifier2->shouldReceive('apply')->once()->with($image);
+
+        $stack = new ModifierStack([$modifier1, $modifier2]);
+        $result = $stack->apply($image);
+        $this->assertInstanceOf(ImageInterface::class, $image);
+    }
 }