diff --git a/tests/data/db_structure.xml b/tests/data/db_structure.xml
index 858c9ab100..371da94483 100644
--- a/tests/data/db_structure.xml
+++ b/tests/data/db_structure.xml
@@ -238,4 +238,59 @@
 	</declaration>
 </table>
 
+	<table>
+		<name>*dbprefix*uniconst</name>
+		<declaration>
+
+			<field>
+				<name>id</name>
+				<type>integer</type>
+				<default>0</default>
+				<notnull>true</notnull>
+				<autoincrement>1</autoincrement>
+				<length>4</length>
+			</field>
+
+			<!-- Foreign Key storages::numeric_id -->
+			<field>
+				<name>storage</name>
+				<type>integer</type>
+				<default></default>
+				<notnull>true</notnull>
+				<length>4</length>
+			</field>
+
+			<field>
+				<name>path_hash</name>
+				<type>text</type>
+				<default></default>
+				<notnull>true</notnull>
+				<length>32</length>
+			</field>
+
+			<field>
+				<name>etag</name>
+				<type>text</type>
+				<default></default>
+				<notnull>false</notnull>
+				<length>40</length>
+			</field>
+
+			<index>
+				<!--<name>fs_storage_path_hash</name>-->
+				<unique>true</unique>
+				<field>
+					<name>storage</name>
+					<sorting>ascending</sorting>
+				</field>
+				<field>
+					<name>path_hash</name>
+					<sorting>ascending</sorting>
+				</field>
+			</index>
+
+		</declaration>
+
+	</table>
+
 </database>
diff --git a/tests/lib/db.php b/tests/lib/db.php
index aefbb3624e..73eef3a4d0 100644
--- a/tests/lib/db.php
+++ b/tests/lib/db.php
@@ -32,13 +32,18 @@ class Test_DB extends \Test\TestCase {
 	 */
 	private $table4;
 
+	/**
+	 * @var string
+	 */
+	private $table5;
+
 	protected function setUp() {
 		parent::setUp();
 
-		$dbfile = OC::$SERVERROOT.'/tests/data/db_structure.xml';
+		$dbFile = OC::$SERVERROOT.'/tests/data/db_structure.xml';
 
-		$r = '_'.OC_Util::generateRandomBytes(4).'_';
-		$content = file_get_contents( $dbfile );
+		$r = $this->getUniqueID('_', 4).'_';
+		$content = file_get_contents( $dbFile );
 		$content = str_replace( '*dbprefix*', '*dbprefix*'.$r, $content );
 		file_put_contents( self::$schema_file, $content );
 		OC_DB::createDbFromStructure(self::$schema_file);
@@ -48,6 +53,7 @@ class Test_DB extends \Test\TestCase {
 		$this->table2 = $this->test_prefix.'cntcts_cards';
 		$this->table3 = $this->test_prefix.'vcategory';
 		$this->table4 = $this->test_prefix.'decimal';
+		$this->table5 = $this->test_prefix.'uniconst';
 	}
 
 	protected function tearDown() {
@@ -110,7 +116,7 @@ class Test_DB extends \Test\TestCase {
 	}
 	
 	public function testinsertIfNotExist() {
-		$categoryentries = array(
+		$categoryEntries = array(
 				array('user' => 'test', 'type' => 'contact', 'category' => 'Family',    'expectedResult' => 1),
 				array('user' => 'test', 'type' => 'contact', 'category' => 'Friends',   'expectedResult' => 1),
 				array('user' => 'test', 'type' => 'contact', 'category' => 'Coworkers', 'expectedResult' => 1),
@@ -118,7 +124,7 @@ class Test_DB extends \Test\TestCase {
 				array('user' => 'test', 'type' => 'contact', 'category' => 'School',    'expectedResult' => 1),
 			);
 
-		foreach($categoryentries as $entry) {
+		foreach($categoryEntries as $entry) {
 			$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table3,
 				array(
 					'uid' => $entry['user'],
@@ -135,13 +141,13 @@ class Test_DB extends \Test\TestCase {
 	}
 
 	public function testInsertIfNotExistNull() {
-		$categoryentries = array(
+		$categoryEntries = array(
 			array('addressbookid' => 123, 'fullname' => null, 'expectedResult' => 1),
 			array('addressbookid' => 123, 'fullname' => null, 'expectedResult' => 0),
 			array('addressbookid' => 123, 'fullname' => 'test', 'expectedResult' => 1),
 		);
 
-		foreach($categoryentries as $entry) {
+		foreach($categoryEntries as $entry) {
 			$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table2,
 				array(
 					'addressbookid' => $entry['addressbookid'],
@@ -156,14 +162,14 @@ class Test_DB extends \Test\TestCase {
 		$this->assertEquals(2, count($result->fetchAll()));
 	}
 
-	public function testinsertIfNotExistDontOverwrite() {
-		$fullname = 'fullname test';
+	public function testInsertIfNotExistDonTOverwrite() {
+		$fullName = 'fullname test';
 		$uri = 'uri_1';
 		$carddata = 'This is a vCard';
 
 		// Normal test to have same known data inserted.
 		$query = OC_DB::prepare('INSERT INTO `*PREFIX*'.$this->table2.'` (`fullname`, `uri`, `carddata`) VALUES (?, ?, ?)');
-		$result = $query->execute(array($fullname, $uri, $carddata));
+		$result = $query->execute(array($fullName, $uri, $carddata));
 		$this->assertEquals(1, $result);
 		$query = OC_DB::prepare('SELECT `fullname`, `uri`, `carddata` FROM `*PREFIX*'.$this->table2.'` WHERE `uri` = ?');
 		$result = $query->execute(array($uri));
@@ -176,7 +182,7 @@ class Test_DB extends \Test\TestCase {
 		// Try to insert a new row
 		$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table2,
 			array(
-				'fullname' => $fullname,
+				'fullname' => $fullName,
 				'uri' => $uri,
 			));
 		$this->assertEquals(0, $result);
@@ -192,6 +198,25 @@ class Test_DB extends \Test\TestCase {
 		$this->assertEquals($carddata, $rowset[0]['carddata']);
 	}
 
+	public function testInsertIfNotExistsViolating() {
+		$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table5,
+			array(
+				'storage' => 1,
+				'path_hash' => md5('welcome.txt'),
+				'etag' => $this->getUniqueID()
+			));
+		$this->assertEquals(1, $result);
+
+		$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table5,
+			array(
+				'storage' => 1,
+				'path_hash' => md5('welcome.txt'),
+				'etag' => $this->getUniqueID()
+			),['storage', 'path_hash']);
+
+		$this->assertEquals(0, $result);
+	}
+
 	public function testUtf8Data() {
 		$table = "*PREFIX*{$this->table2}";
 		$expected = "Ћö雙喜\xE2\x80\xA2";