Clean up after passing Collection functional tests

tests/Collection/CrudSpec/AggregateFunctionalTest.php

@@ -55,5 +55,8 @@ class AggregateFunctionalTest extends FunctionalTestCase
         );
 
         $this->assertSame($expected, $outputCollection->find()->toArray());
+
+        // Manually clean up our output collection
+        $this->dropCollectionIfItExists($outputCollection);
     }
 }

tests/Collection/FunctionalTestCase.php

@@ -21,6 +21,15 @@ abstract class FunctionalTestCase extends BaseFunctionalTestCase
         $this->dropCollectionIfItExists($this->collection);
     }
 
+    public function tearDown()
+    {
+        if ($this->hasFailed()) {
+            return;
+        }
+
+        $this->dropCollectionIfItExists($this->collection);
+    }
+
     /**
      * Drop the collection if it exists.
      *