PHPLIB-682: Add test for Database::dropCollection()

Author: tanlisu

tests/Database/DatabaseFunctionalTest.php

@@ -158,6 +158,19 @@ public function testDrop(): void
         $this->assertCollectionCount($this->getNamespace(), 0);
     }
 
+    public function testDropCollection(): void
+    {
+        $bulkWrite = new BulkWrite();
+        $bulkWrite->insert(['x' => 1]);
+
+        $writeResult = $this->manager->executeBulkWrite($this->getNamespace(), $bulkWrite);
+        $this->assertEquals(1, $writeResult->getInsertedCount());
+
+        $commandResult = $this->database->dropCollection($this->getCollectionName());
+        $this->assertCommandSucceeded($commandResult);
+        $this->assertCollectionCount($this->getNamespace(), 0);
+    }
+
     public function testGetSelectsCollectionAndInheritsOptions(): void
     {
         $databaseOptions = ['writeConcern' => new WriteConcern(WriteConcern::MAJORITY)];