diff --git a/src/Extend/Addon.php b/src/Extend/Addon.php
index bc5d3e8cda..94fd2b5554 100644
--- a/src/Extend/Addon.php
+++ b/src/Extend/Addon.php
@@ -402,7 +402,7 @@ public function __call($method, $args)
     }
 
     /**
-     * The directory the package is located within. eg. "/path/to/vendor/statamic/bloodhound".
+     * The directory the package is located within. eg. "/path/to/vendor/statamic/bloodhound/".
      *
      * @return string
      */
@@ -420,7 +420,7 @@ public function directory()
 
         $dir = Str::removeRight(dirname($reflector->getFileName()), rtrim($this->autoload, '/'));
 
-        return $this->directory = Str::removeRight($dir, '/');
+        return $this->directory = Str::ensureRight($dir, '/');
     }
 
     public function existsOnMarketplace()
diff --git a/tests/Extend/AddonTest.php b/tests/Extend/AddonTest.php
index 9fa4cb3dde..dbaaf41664 100644
--- a/tests/Extend/AddonTest.php
+++ b/tests/Extend/AddonTest.php
@@ -16,7 +16,7 @@ class AddonTest extends TestCase
     public function setUp(): void
     {
         parent::setUp();
-        $this->addonFixtureDir = realpath(__DIR__.'/../Fixtures/Addon');
+        $this->addonFixtureDir = realpath(__DIR__.'/../Fixtures/Addon').'/';
     }
 
     /** @test */
@@ -123,8 +123,8 @@ public function it_checks_if_a_file_exists()
     {
         $addon = $this->makeFromPackage();
 
-        File::shouldReceive('exists')->with($this->addonFixtureDir.'/test.txt')->andReturnTrue();
-        File::shouldReceive('exists')->with($this->addonFixtureDir.'/notfound.txt')->andReturnFalse();
+        File::shouldReceive('exists')->with($this->addonFixtureDir.'test.txt')->andReturnTrue();
+        File::shouldReceive('exists')->with($this->addonFixtureDir.'notfound.txt')->andReturnFalse();
 
         $this->assertTrue($addon->hasFile('test.txt'));
         $this->assertFalse($addon->hasFile('notfound.txt'));
@@ -135,7 +135,7 @@ public function it_gets_file_contents()
     {
         $addon = $this->makeFromPackage();
 
-        File::shouldReceive('get')->with($this->addonFixtureDir.'/test.txt')->andReturn('the file contents');
+        File::shouldReceive('get')->with($this->addonFixtureDir.'test.txt')->andReturn('the file contents');
 
         $this->assertEquals('the file contents', $addon->getFile('test.txt'));
     }
@@ -145,7 +145,7 @@ public function it_writes_file_contents()
     {
         $addon = $this->makeFromPackage();
 
-        File::shouldReceive('put')->with($this->addonFixtureDir.'/test.txt', 'the file contents');
+        File::shouldReceive('put')->with($this->addonFixtureDir.'test.txt', 'the file contents');
 
         $addon->putFile('test.txt', 'the file contents');
     }