diff --git a/.travis.yml b/.travis.yml
index e89cf27820..6453b97ae9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -96,7 +96,6 @@ before_install:
       echo apc.enable_cli = 1 >> $INI
       echo extension = redis.so >> $INI
       echo extension = memcached.so >> $INI
-      echo extension = mongodb.so >> $INI
 
       # Matrix lines for intermediate PHP versions are skipped for pull requests
       if [[ ! $deps && ! $PHP = $MIN_PHP && $TRAVIS_PULL_REQUEST != false ]]; then
@@ -115,8 +114,9 @@ before_install:
 
     - |
       # Install extra PHP extensions
-      if [[ ! $skip && $PHP = 7.* ]]; then
+      if [[ ! $skip ]]; then
           tfold ext.apcu5 'echo yes | pecl install -f apcu-5.1.6'
+          tfold ext.mongodb pecl install -f mongodb-1.4.0RC1
       fi
 
     - |
diff --git a/src/Symfony/Component/CssSelector/Tests/CssSelectorConverterTest.php b/src/Symfony/Component/CssSelector/Tests/CssSelectorConverterTest.php
index a27fadfef1..a3eea7ad21 100644
--- a/src/Symfony/Component/CssSelector/Tests/CssSelectorConverterTest.php
+++ b/src/Symfony/Component/CssSelector/Tests/CssSelectorConverterTest.php
@@ -59,7 +59,7 @@ class CssSelectorConverterTest extends TestCase
             array('h1', 'h1'),
             array('foo|h1', 'foo:h1'),
             array('h1, h2, h3', 'h1 | h2 | h3'),
-            array('h1:nth-child(3n+1)', "*/*[name() = 'h1' and (position() - 1 >= 0 and (position() - 1) mod 3 = 0)]"),
+            array('h1:nth-child(3n+1)', "*/*[(name() = 'h1') and (position() - 1 >= 0 and (position() - 1) mod 3 = 0)]"),
             array('h1 > p', 'h1/p'),
             array('h1#foo', "h1[@id = 'foo']"),
             array('h1.foo', "h1[@class and contains(concat(' ', normalize-space(@class), ' '), ' foo ')]"),
diff --git a/src/Symfony/Component/CssSelector/Tests/XPath/TranslatorTest.php b/src/Symfony/Component/CssSelector/Tests/XPath/TranslatorTest.php
index 218a3b43c1..519417835c 100644
--- a/src/Symfony/Component/CssSelector/Tests/XPath/TranslatorTest.php
+++ b/src/Symfony/Component/CssSelector/Tests/XPath/TranslatorTest.php
@@ -102,18 +102,20 @@ class TranslatorTest extends TestCase
             array('e[foo^="bar"]', "e[@foo and starts-with(@foo, 'bar')]"),
             array('e[foo$="bar"]', "e[@foo and substring(@foo, string-length(@foo)-2) = 'bar']"),
             array('e[foo*="bar"]', "e[@foo and contains(@foo, 'bar')]"),
+            array('e[foo!="bar"]', "e[not(@foo) or @foo != 'bar']"),
+            array('e[foo!="bar"][foo!="baz"]', "e[(not(@foo) or @foo != 'bar') and (not(@foo) or @foo != 'baz')]"),
             array('e[hreflang|="en"]', "e[@hreflang and (@hreflang = 'en' or starts-with(@hreflang, 'en-'))]"),
-            array('e:nth-child(1)', "*/*[name() = 'e' and (position() = 1)]"),
-            array('e:nth-last-child(1)', "*/*[name() = 'e' and (position() = last() - 0)]"),
-            array('e:nth-last-child(2n+2)', "*/*[name() = 'e' and (last() - position() - 1 >= 0 and (last() - position() - 1) mod 2 = 0)]"),
+            array('e:nth-child(1)', "*/*[(name() = 'e') and (position() = 1)]"),
+            array('e:nth-last-child(1)', "*/*[(name() = 'e') and (position() = last() - 0)]"),
+            array('e:nth-last-child(2n+2)', "*/*[(name() = 'e') and (last() - position() - 1 >= 0 and (last() - position() - 1) mod 2 = 0)]"),
             array('e:nth-of-type(1)', '*/e[position() = 1]'),
             array('e:nth-last-of-type(1)', '*/e[position() = last() - 0]'),
             array('div e:nth-last-of-type(1) .aclass', "div/descendant-or-self::*/e[position() = last() - 0]/descendant-or-self::*/*[@class and contains(concat(' ', normalize-space(@class), ' '), ' aclass ')]"),
-            array('e:first-child', "*/*[name() = 'e' and (position() = 1)]"),
-            array('e:last-child', "*/*[name() = 'e' and (position() = last())]"),
+            array('e:first-child', "*/*[(name() = 'e') and (position() = 1)]"),
+            array('e:last-child', "*/*[(name() = 'e') and (position() = last())]"),
             array('e:first-of-type', '*/e[position() = 1]'),
             array('e:last-of-type', '*/e[position() = last()]'),
-            array('e:only-child', "*/*[name() = 'e' and (last() = 1)]"),
+            array('e:only-child', "*/*[(name() = 'e') and (last() = 1)]"),
             array('e:only-of-type', 'e[last() = 1]'),
             array('e:empty', 'e[not(*) and not(string-length())]'),
             array('e:EmPTY', 'e[not(*) and not(string-length())]'),
@@ -127,7 +129,7 @@ class TranslatorTest extends TestCase
             array('e:nOT(*)', 'e[0]'),
             array('e f', 'e/descendant-or-self::*/f'),
             array('e > f', 'e/f'),
-            array('e + f', "e/following-sibling::*[name() = 'f' and (position() = 1)]"),
+            array('e + f', "e/following-sibling::*[(name() = 'f') and (position() = 1)]"),
             array('e ~ f', 'e/following-sibling::f'),
             array('div#container p', "div[@id = 'container']/descendant-or-self::*/p"),
         );
diff --git a/src/Symfony/Component/CssSelector/XPath/XPathExpr.php b/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
index 0b958fa1ad..8090df9907 100644
--- a/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
+++ b/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
@@ -45,7 +45,7 @@ class XPathExpr
 
     public function addCondition(string $condition): XPathExpr
     {
-        $this->condition = $this->condition ? sprintf('%s and (%s)', $this->condition, $condition) : $condition;
+        $this->condition = $this->condition ? sprintf('(%s) and (%s)', $this->condition, $condition) : $condition;
 
         return $this;
     }
@@ -77,7 +77,7 @@ class XPathExpr
      *
      * @return $this
      */
-    public function join(string $combiner, XPathExpr $expr): XPathExpr
+    public function join(string $combiner, self $expr): self
     {
         $path = $this->__toString().$combiner;
 
diff --git a/src/Symfony/Component/Debug/Tests/Exception/FlattenExceptionTest.php b/src/Symfony/Component/Debug/Tests/Exception/FlattenExceptionTest.php
index c4cf58315a..5c781dbf42 100644
--- a/src/Symfony/Component/Debug/Tests/Exception/FlattenExceptionTest.php
+++ b/src/Symfony/Component/Debug/Tests/Exception/FlattenExceptionTest.php
@@ -111,7 +111,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testFlattenHttpException(\Exception $exception, $statusCode)
+    public function testFlattenHttpException(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened2 = FlattenException::create($exception);
@@ -126,7 +126,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testPrevious(\Exception $exception, $statusCode)
+    public function testPrevious(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened2 = FlattenException::create($exception);
@@ -170,7 +170,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testToArray(\Exception $exception, $statusCode)
+    public function testToArray(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened->setTrace(array(), 'foo.php', 123);
@@ -190,7 +190,7 @@ class FlattenExceptionTest extends TestCase
     public function flattenDataProvider()
     {
         return array(
-            array(new \Exception('test', 123), 500),
+            array(new \Exception('test', 123)),
         );
     }