diff --git a/tests/core/command/maintenance/mimetype/updatedbtest.php b/tests/core/command/maintenance/mimetype/updatedbtest.php
new file mode 100644
index 0000000000..217301102c
--- /dev/null
+++ b/tests/core/command/maintenance/mimetype/updatedbtest.php
@@ -0,0 +1,184 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace Tests\Core\Command\Maintenance\Mimetype;
+
+use OC\Core\Command\Maintenance\Mimetype\UpdateDB;
+use Test\TestCase;
+use OCP\Files\IMimeTypeDetector;
+use OCP\Files\IMimeTypeLoader;
+
+class UpdateDBTest extends TestCase {
+	/** @var IMimeTypeDetector */
+	protected $detector;
+	/** @var IMimeTypeLoader */
+	protected $loader;
+
+	/** @var \PHPUnit_Framework_MockObject_MockObject */
+	protected $consoleInput;
+	/** @var \PHPUnit_Framework_MockObject_MockObject */
+	protected $consoleOutput;
+
+	/** @var \Symfony\Component\Console\Command\Command */
+	protected $command;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->detector = $this->getMockBuilder('OC\Files\Type\Detection')
+			->disableOriginalConstructor()
+			->getMock();
+		$this->loader = $this->getMockBuilder('OC\Files\Type\Loader')
+			->disableOriginalConstructor()
+			->getMock();
+
+		$this->consoleInput = $this->getMock('Symfony\Component\Console\Input\InputInterface');
+		$this->consoleOutput = $this->getMock('Symfony\Component\Console\Output\OutputInterface');
+
+		$this->command = new UpdateDB($this->detector, $this->loader);
+	}
+
+	public function testNoop() {
+		$this->consoleInput->method('getOption')
+			->with('repair-filecache')
+			->willReturn(false);
+
+		$this->detector->expects($this->once())
+			->method('getAllMappings')
+			->willReturn([
+				'ext' => ['testing/existingmimetype']
+			]);
+		$this->loader->expects($this->once())
+			->method('exists')
+			->with('testing/existingmimetype')
+			->willReturn(true);
+
+		$this->loader->expects($this->never())
+			->method('updateFilecache');
+
+		$this->consoleOutput->expects($this->at(0))
+			->method('writeln')
+			->with('Added 0 new mimetypes');
+		$this->consoleOutput->expects($this->at(1))
+			->method('writeln')
+			->with('Updated 0 filecache rows');
+
+		self::invokePrivate($this->command, 'execute', [$this->consoleInput, $this->consoleOutput]);
+	}
+
+	public function testAddMimetype() {
+		$this->consoleInput->method('getOption')
+			->with('repair-filecache')
+			->willReturn(false);
+
+		$this->detector->expects($this->once())
+			->method('getAllMappings')
+			->willReturn([
+				'ext' => ['testing/existingmimetype'],
+				'new' => ['testing/newmimetype']
+			]);
+		$this->loader->expects($this->exactly(2))
+			->method('exists')
+			->will($this->returnValueMap([
+				['testing/existingmimetype', true],
+				['testing/newmimetype', false],
+			]));
+		$this->loader->expects($this->exactly(2))
+			->method('getId')
+			->will($this->returnValueMap([
+				['testing/existingmimetype', 1],
+				['testing/newmimetype', 2],
+			]));
+
+		$this->loader->expects($this->once())
+			->method('updateFilecache')
+			->with('new', 2)
+			->willReturn(3);
+
+		$this->consoleOutput->expects($this->at(0))
+			->method('writeln')
+			->with('Added mimetype "testing/newmimetype" to database');
+		$this->consoleOutput->expects($this->at(1))
+			->method('writeln')
+			->with('Updated 3 filecache rows for mimetype "testing/newmimetype"');
+
+		$this->consoleOutput->expects($this->at(2))
+			->method('writeln')
+			->with('Added 1 new mimetypes');
+		$this->consoleOutput->expects($this->at(3))
+			->method('writeln')
+			->with('Updated 3 filecache rows');
+
+		self::invokePrivate($this->command, 'execute', [$this->consoleInput, $this->consoleOutput]);
+	}
+
+	public function testSkipComments() {
+		$this->detector->expects($this->once())
+			->method('getAllMappings')
+			->willReturn([
+				'_comment' => 'some comment in the JSON'
+			]);
+		$this->loader->expects($this->never())
+			->method('exists');
+
+		self::invokePrivate($this->command, 'execute', [$this->consoleInput, $this->consoleOutput]);
+	}
+
+	public function testRepairFilecache() {
+		$this->consoleInput->method('getOption')
+			->with('repair-filecache')
+			->willReturn(true);
+
+		$this->detector->expects($this->once())
+			->method('getAllMappings')
+			->willReturn([
+				'ext' => ['testing/existingmimetype'],
+			]);
+		$this->loader->expects($this->exactly(1))
+			->method('exists')
+			->will($this->returnValueMap([
+				['testing/existingmimetype', true],
+			]));
+		$this->loader->expects($this->exactly(1))
+			->method('getId')
+			->will($this->returnValueMap([
+				['testing/existingmimetype', 1],
+			]));
+
+		$this->loader->expects($this->once())
+			->method('updateFilecache')
+			->with('ext', 1)
+			->willReturn(3);
+
+		$this->consoleOutput->expects($this->at(0))
+			->method('writeln')
+			->with('Updated 3 filecache rows for mimetype "testing/existingmimetype"');
+
+		$this->consoleOutput->expects($this->at(1))
+			->method('writeln')
+			->with('Added 0 new mimetypes');
+		$this->consoleOutput->expects($this->at(2))
+			->method('writeln')
+			->with('Updated 3 filecache rows');
+
+		self::invokePrivate($this->command, 'execute', [$this->consoleInput, $this->consoleOutput]);
+	}
+}
diff --git a/tests/lib/files/type/loadertest.php b/tests/lib/files/type/loadertest.php
new file mode 100644
index 0000000000..7f87afd2f4
--- /dev/null
+++ b/tests/lib/files/type/loadertest.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\Files\Type;
+
+use \OC\Files\Type\Loader;
+use \OCP\IDBConnection;
+
+class LoaderTest extends \Test\TestCase {
+	/** @var IDBConnection */
+	protected $db;
+	/** @var Loader */
+	protected $loader;
+
+	protected function setUp() {
+		$this->db = \OC::$server->getDatabaseConnection();
+		$this->loader = new Loader($this->db);
+	}
+
+	protected function tearDown() {
+		$deleteMimetypes = $this->db->getQueryBuilder();
+		$deleteMimetypes->delete('mimetypes')
+			->where($deleteMimetypes->expr()->like(
+				'mimetype', $deleteMimetypes->createPositionalParameter('testing/%')
+			));
+		$deleteMimetypes->execute();
+	}
+
+
+	public function testGetMimetype() {
+		$qb = $this->db->getQueryBuilder();
+		$qb->insert('mimetypes')
+			->values([
+				'mimetype' => $qb->createPositionalParameter('testing/mymimetype')
+			]);
+		$qb->execute();
+
+		$this->assertTrue($this->loader->exists('testing/mymimetype'));
+		$mimetypeId = $this->loader->getId('testing/mymimetype');
+		$this->assertNotNull($mimetypeId);
+
+		$mimetype = $this->loader->getMimetypeById($mimetypeId);
+		$this->assertEquals('testing/mymimetype', $mimetype);
+	}
+
+	public function testGetNonexistentMimetype() {
+		$this->assertFalse($this->loader->exists('testing/nonexistent'));
+		// hopefully this ID doesn't exist
+		$this->assertNull($this->loader->getMimetypeById(12345));
+	}
+
+	public function testStore() {
+		$this->assertFalse($this->loader->exists('testing/mymimetype'));
+		$mimetypeId = $this->loader->getId('testing/mymimetype');
+
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('mimetype')
+			->from('mimetypes')
+			->where($qb->expr()->eq('id', $qb->createPositionalParameter($mimetypeId)));
+
+		$mimetype = $qb->execute()->fetch();
+		$this->assertEquals('testing/mymimetype', $mimetype['mimetype']);
+
+		$this->assertEquals('testing/mymimetype', $this->loader->getMimetypeById($mimetypeId));
+		$this->assertEquals($mimetypeId, $this->loader->getId('testing/mymimetype'));
+	}
+
+	public function testStoreExists() {
+		$mimetypeId = $this->loader->getId('testing/mymimetype');
+		$mimetypeId2 = $this->loader->getId('testing/mymimetype');
+
+		$this->assertEquals($mimetypeId, $mimetypeId2);
+	}
+
+}