Merge branch 'hotfix/9'

Close #9

src/PriorityList.php

@@ -62,8 +62,11 @@ class PriorityList implements Iterator, Countable
      */
     public function insert($name, $value, $priority = 0)
     {
+        if (!isset($this->items[$name])) {
+            $this->count++;
+        }
+
         $this->sorted = false;
-        $this->count++;
 
         $this->items[$name] = [
             'data'     => $value,

test/PriorityListTest.php

@@ -35,6 +35,24 @@ public function testInsert()
         }
     }
 
+    public function testInsertDuplicates()
+    {
+        $this->list->insert('foo', new \stdClass());
+        $this->list->insert('bar', new \stdClass());
+
+        $this->assertEquals(2, count($this->list));
+
+        $this->list->insert('foo', new \stdClass());
+        $this->list->insert('foo', new \stdClass());
+        $this->list->insert('bar', new \stdClass());
+
+        $this->assertEquals(2, count($this->list));
+
+        $this->list->remove('foo');
+
+        $this->assertEquals(1, count($this->list));
+    }
+
     public function testRemove()
     {
         $this->list->insert('foo', new \stdClass(), 0);