diff --git a/tests/HelperTest.php b/tests/HelperTest.php
index cbcf92b..e0d9a19 100644
--- a/tests/HelperTest.php
+++ b/tests/HelperTest.php
@@ -41,6 +41,35 @@ public function testSet()
         $this->assertSame(['a' => 'A', 'b' => 'B', 'c' => 'C'], $_SESSION);
     }
 
+    public function testAssocSet()
+    {
+        $helper = new Helper();
+        
+        $helper->set('a', ['b' => 'B']);
+        $this->assertSame(['a' => ['b' => 'B']], $_SESSION);
+
+        $helper->b = ['c' => 'C'];
+        $this->assertSame(['a' => ['b' => 'B'], 'b' => ['c' => 'C']], $_SESSION);
+
+        $helper['c'] = ['d' => 'D'];
+        $this->assertSame(['a' => ['b' => 'B'], 'b' => ['c' => 'C'], 'c' => ['d' => 'D']], $_SESSION);
+    }
+
+    public function testMergeSet()
+    {
+        $helper = new Helper();
+        $helper->set('a', []);
+
+        $helper->set('a', ['a' => 'A']);
+        $this->assertSame(['a' => ['a' => 'A']], $_SESSION);
+
+        $helper->a = ['b' => 'B'];
+        $this->assertSame(['a' => ['a' => 'A', 'b' => 'B']], $_SESSION);
+
+        $helper['a'] = ['c' => 'C'];
+        $this->assertSame(['a' => ['a' => 'A', 'b' => 'B', 'c' => 'C']], $_SESSION);
+    }
+
     public function testGet()
     {
         $helper = new Helper();