diff --git a/src/Interfaces/CurlInterface.php b/src/Interfaces/CurlInterface.php
index 7fc82dd..ded8079 100644
--- a/src/Interfaces/CurlInterface.php
+++ b/src/Interfaces/CurlInterface.php
@@ -20,7 +20,9 @@
  */
 interface CurlInterface
 {
-    public function handle(): CurlHandle;
+    public function __destruct();
+
+    public function handle(): ?CurlHandle;
 
     public function error(): string;
 
diff --git a/src/Traits/CurlTrait.php b/src/Traits/CurlTrait.php
index 5dc1e95..e391bf2 100644
--- a/src/Traits/CurlTrait.php
+++ b/src/Traits/CurlTrait.php
@@ -51,9 +51,9 @@ public function __destruct()
         }
     }
 
-    public function handle(): CurlHandle
+    public function handle(): ?CurlHandle
     {
-        return $this->handle;
+        return isset($this->handle) ? $this->handle : null;
     }
 
     public function error(): string
@@ -73,7 +73,7 @@ public function setOptArray(array $options): bool
 
     public function close(): void
     {
-        curl_close($this->handle);
+        unset($this->handle);
     }
 
     private function assertCurl(): void
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 877a6d1..8eeb0fb 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -59,6 +59,12 @@ public function testPost(): void
             CURLOPT_USERAGENT => 'chevere/xr 1.0',
         ];
         $this->assertSame($options, $client->options());
+        $curl = $this->createMock(Curl::class);
+        $curl->expects($this->once())
+            ->method('setOptArray')
+            ->with($options);
+        $client = $client->withCurl($curl);
+        $client->sendMessage($message);
     }
 
     public function testCustom(): void