diff --git a/Query/Span/SpanFirstQueryTest.php b/Query/Span/SpanFirstQueryTest.php
index 6805ed4936c320dc722831e7daed2eab0905a2b4..9b1e4d1ef867e68d0ea3ab62835d837f5ed3d472 100644
--- a/Query/Span/SpanFirstQueryTest.php
+++ b/Query/Span/SpanFirstQueryTest.php
@@ -43,7 +43,7 @@ class SpanFirstQueryTest extends \PHPUnit_Framework_TestCase
      */
     public function tearDown()
     {
-        $this->mock = null;
+        unset($this->mock);
     }
 
     /**
diff --git a/Query/Span/SpanMultiTermQueryTest.php b/Query/Span/SpanMultiTermQueryTest.php
index d692a26b9f5e95ca43bbeb28661d9790f276f7e1..dbbfe4edad1b212e6a434d090e0d49f24ea5f693 100644
--- a/Query/Span/SpanMultiTermQueryTest.php
+++ b/Query/Span/SpanMultiTermQueryTest.php
@@ -49,7 +49,7 @@ class SpanMultiTermQueryTest extends \PHPUnit_Framework_TestCase
      */
     public function tearDown()
     {
-        $this->mock = null;
+        unset($this->mock);
     }
 
     /**
diff --git a/Query/Span/SpanNearQueryTest.php b/Query/Span/SpanNearQueryTest.php
index 0962be4d40742448d35c25752f32fc74bd2548e8..ebdcfbc6d1ce43248aa03e59e050e9a09357cd0b 100644
--- a/Query/Span/SpanNearQueryTest.php
+++ b/Query/Span/SpanNearQueryTest.php
@@ -43,7 +43,7 @@ class SpanNearQueryTest extends \PHPUnit_Framework_TestCase
      */
     public function tearDown()
     {
-        $this->mock = null;
+        unset($this->mock);
     }
 
     /**
diff --git a/Query/Span/SpanNotQueryTest.php b/Query/Span/SpanNotQueryTest.php
index 891b80e48150399a076e8e4eebb3be4d4b6027c5..df6856a8bb455c8e8674559917b9c0f8f4caca19 100644
--- a/Query/Span/SpanNotQueryTest.php
+++ b/Query/Span/SpanNotQueryTest.php
@@ -43,7 +43,7 @@ class SpanNotQueryTest extends \PHPUnit_Framework_TestCase
      */
     public function tearDown()
     {
-        $this->mock = null;
+        unset($this->mock);
     }
 
     /**
diff --git a/Query/Span/SpanOrQueryTest.php b/Query/Span/SpanOrQueryTest.php
index 67aeb81780a29c3a8fa67fd8b2fa7263e64294e3..d69e550206511b5c896a5071c344262a9cc4172d 100644
--- a/Query/Span/SpanOrQueryTest.php
+++ b/Query/Span/SpanOrQueryTest.php
@@ -43,7 +43,7 @@ class SpanOrQueryTest extends \PHPUnit_Framework_TestCase
      */
     public function tearDown()
     {
-        $this->mock = null;
+        unset($this->mock);
     }
 
     /**