PHPLIB-107: Do not throw when dropping nonexistent collection

src/Operation/DropCollection.php

@@ -4,6 +4,7 @@ namespace MongoDB\Operation;
 
 use MongoDB\Driver\Command;
 use MongoDB\Driver\Server;
+use MongoDB\Driver\Exception\RuntimeException as DriverRuntimeException;
 use MongoDB\Exception\RuntimeException;
 
 /**
@@ -40,7 +41,16 @@ class DropCollection implements Executable
      */
     public function execute(Server $server)
     {
-        $cursor = $server->executeCommand($this->databaseName, new Command(array('drop' => $this->collectionName)));
+        try {
+            $cursor = $server->executeCommand($this->databaseName, new Command(array('drop' => $this->collectionName)));
+        } catch (DriverRuntimeException $e) {
+            if ($e->getMessage() === 'ns not found') {
+                $result = (object) ['ok' => 0, 'errmsg' => 'ns not found'];
+            }
+
+            throw $e;
+        }
+
         $result = current($cursor->toArray());
 
         if (empty($result->ok)) {

tests/Operation/DropCollectionFunctionalTest.php

+<?php
+
+namespace MongoDB\Tests\Operation;
+
+use MongoDB\Driver\Server;
+use MongoDB\Operation\DropCollection;
+use MongoDB\Operation\ListCollections;
+
+class DropCollectionFunctionalTest extends FunctionalTestCase
+{
+    public function testDropExistingCollection()
+    {
+        $writeResult = $this->manager->executeInsert($this->getNamespace(), array('x' => 1));
+        $this->assertEquals(1, $writeResult->getInsertedCount());
+
+        $server = $this->getPrimaryServer();
+        $operation = new DropCollection($this->getDatabaseName(), $this->getCollectionName());
+        $operation->execute($server);
+
+        $this->assertCollectionDoesNotExist($server, $this->getDatabaseName(), $this->getCollectionName());
+    }
+
+    /**
+     * @depends testDropExistingCollection
+     */
+    public function testDropNonexistentCollection()
+    {
+        $server = $this->getPrimaryServer();
+
+        $this->assertCollectionDoesNotExist($server, $this->getDatabaseName(), $this->getCollectionName());
+
+        $operation = new DropCollection($this->getDatabaseName(), $this->getCollectionName());
+        $operation->execute($server);
+    }
+
+    /**
+     * Asserts that a collection with the given name does not exist on the
+     * server.
+     *
+     * @param Server $server
+     * @param string $databaseName
+     * @param string $collectionName
+     */
+    private function assertCollectionDoesNotExist(Server $server, $databaseName, $collectionName)
+    {
+        $operation = new ListCollections($databaseName);
+        $collections = $operation->execute($server);
+
+        $foundCollection = null;
+
+        foreach ($collections as $collection) {
+            if ($collection->getName() === $collectionName) {
+                $foundCollection = $collection;
+                break;
+            }
+        }
+
+        $this->assertNull($foundCollection, sprintf('Collection %s exists on the server', $collectionName));
+    }
+}

tests/Operation/FunctionalTestCase.php

+<?php
+
+namespace MongoDB\Tests\Operation;
+
+use MongoDB\Driver\ReadPreference;
+use MongoDB\Tests\FunctionalTestCase as BaseFunctionalTestCase;
+
+/**
+ * Base class for Operation functional tests.
+ */
+abstract class FunctionalTestCase extends BaseFunctionalTestCase
+{
+    public function getPrimaryServer()
+    {
+        return $this->manager->selectServer(new ReadPreference(ReadPreference::RP_PRIMARY));
+    }
+}