Add cleanup: dirty config option (#1)

* Added `cleanup: dirty` config option.

If cleanup is set to 'dirty', the dump is only reloaded if any data has been written to the db during a test. This is
checked using the [dbHash](https://docs.mongodb.com/manual/reference/command/dbHash/) command.

* Fix documentation of 'cleanup: dirty'.
Update docblock above class definition.

Author: jasny

documentation.md

@@ -38,7 +38,9 @@ HINT: This module can be used with [Mongofill](https://github.com/mongofill/mong
   default: MongoDb::DUMP_TYPE_JS).
 * dump - path to database dump
 * populate: true - should the dump be loaded before test suite is started.
-* cleanup: true - should the dump be reloaded after each test
+* cleanup: true - should the dump be reloaded after each test.
+  Boolean or 'dirty'. If cleanup is set to 'dirty', the dump is only reloaded if any data has been written to the db during a test. This is
+  checked using the [dbHash](https://docs.mongodb.com/manual/reference/command/dbHash/) command.
 
 
 ## Actions

src/Codeception/Lib/Driver/MongoDb.php

@@ -235,6 +235,17 @@ public function setDatabase($dbName)
         $this->dbh = $this->client->{$this->legacy ? 'selectDB' : 'selectDatabase'}($dbName);
     }
 
+    public function getDbHash()
+    {
+        $result = $this->dbh->command(['dbHash' => 1]);
+
+        if (!is_array($result)) {
+            $result = iterator_to_array($result);
+        }
+
+        return isset($result[0]->md5) ? $result[0]->md5 : null;
+    }
+
     /**
      * Determine if this driver is using the legacy extension or not.
      *

src/Codeception/Module/MongoDb.php

@@ -47,7 +47,9 @@
  *   default: MongoDb::DUMP_TYPE_JS).
  * * dump - path to database dump
  * * populate: true - should the dump be loaded before test suite is started.
- * * cleanup: true - should the dump be reloaded after each test
+ * * cleanup: true - should the dump be reloaded after each test.
+ *   Boolean or 'dirty'. If cleanup is set to 'dirty', the dump is only reloaded if any data has been written to the db during a test. This is
+ *   checked using the [dbHash](https://docs.mongodb.com/manual/reference/command/dbHash/) command.
  *
  */
 class MongoDb extends CodeceptionModule implements RequiresPackage
@@ -69,6 +71,8 @@ class MongoDb extends CodeceptionModule implements RequiresPackage
     protected $dumpFile;
     protected $isDumpFileEmpty = true;
 
+    protected $dbHash;
+
     protected $config = [
         'populate'  => true,
         'cleanup'   => true,
@@ -180,7 +184,7 @@ private function validateDump()
 
     public function _before(TestInterface $test)
     {
-        if ($this->config['cleanup'] && !$this->populated) {
+        if ($this->shouldCleanup()) {
             $this->cleanup();
             $this->loadDump();
         }
@@ -191,6 +195,17 @@ public function _after(TestInterface $test)
         $this->populated = false;
     }
 
+    protected function shouldCleanup()
+    {
+        if ($this->populated) {
+            return false;
+        }
+
+        return $this->config['cleanup'] === 'dirty'
+            ? ($this->dbHash === null || $this->driver->getDbHash() !== $this->dbHash)
+            : (bool)$this->config['cleanup'];
+    }
+
     protected function cleanup()
     {
         $dbh = $this->driver->getDbh();
@@ -230,6 +245,10 @@ protected function loadDump()
         } catch (\Exception $e) {
             throw new ModuleException(__CLASS__, $e->getMessage());
         }
+
+        if ($this->config['cleanup'] === 'dirty') {
+            $this->dbHash = $this->driver->getDbHash();
+        }
     }
 
     /**

tests/unit/Codeception/Module/MongoDbTest.php

@@ -36,11 +36,14 @@ protected function _setUp()
             $this->markTestSkipped('MongoDB is not installed');
         }
 
+        $cleanupDirty = in_array('cleanup-dirty', $this->getGroups());
+        $config = $this->mongoConfig + ['cleanup' => $cleanupDirty ? 'dirty' : true];
+
         $mongo = new \MongoDB\Client();
 
         $container = \Codeception\Util\Stub::make('Codeception\Lib\ModuleContainer');
         $this->module = new MongoDb($container);
-        $this->module->_setConfig($this->mongoConfig);
+        $this->module->_setConfig($config);
         try {
             $this->module->_initialize();
         } catch (ModuleException $e) {
@@ -49,7 +52,10 @@ protected function _setUp()
 
         $this->db = $mongo->selectDatabase('test');
         $this->userCollection = $this->db->users;
-        $this->userCollection->insertOne(array('id' => 1, 'email' => '[email protected]'));
+
+        if (!$cleanupDirty) {
+            $this->userCollection->insertOne(array('id' => 1, 'email' => '[email protected]'));
+        }
     }
 
     protected function _tearDown()
@@ -168,4 +174,43 @@ public function testLoadDump()
             $this->module->haveInCollection('96_bulls', $testRecord);
         }
     }
+
+    /**
+     * @group cleanup-dirty
+     */
+    public function testCleanupDirty()
+    {
+        $test = $this->createMock('Codeception\TestInterface');
+        $collection = $this->db->selectCollection('96_bulls');
+
+        $hash1 = $this->module->driver->getDbHash();
+        $this->module->seeNumElementsInCollection('96_bulls', 7);
+        $this->assertEquals($hash1, $this->module->driver->getDbHash());
+
+        $this->module->_after($test);
+
+        $this->module->_before($test); // No cleanup expected
+
+        $this->assertEquals($hash1, $this->module->driver->getDbHash());
+        $collection->insertOne(array('name' => 'Coby White','position' => 'pg'));
+
+        $hashDirty = $this->module->driver->getDbHash();
+        $this->assertNotEquals($hash1, $hashDirty);
+
+        $this->module->_after($test);
+
+        $this->module->_before($test); // Cleanup expected
+        $this->module->seeNumElementsInCollection('96_bulls', 7);
+
+        $hash2 = $this->module->driver->getDbHash();
+
+        $this->assertNotEquals($hash1, $hash2);
+        $this->assertNotEquals($hashDirty, $hash2);
+
+        $this->module->_after($test);
+
+        $this->module->_before($test); // No cleanup expected
+
+        $this->assertEquals($hash2, $this->module->driver->getDbHash());
+    }
 }