diff --git a/.travis.yml b/.travis.yml
index 03ee7365..dff6b451 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ cache:
 
 env:
   global:
-    - COMPOSER_ARGS="--no-interaction"
+    - COMPOSER_ARGS="--no-interaction --no-plugins"
     - COVERAGE_DEPS="php-coveralls/php-coveralls"
 
 matrix:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ee28cee..876215d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,7 +22,7 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
+- [#7](https://github.com/mezzio/mezzio-swoole/pull/7) fixes default value for SameSite in Cookie of Swoole\Http\Response.
 
 ## 2.6.1 - 2020-03-28
 
diff --git a/src/SwooleEmitter.php b/src/SwooleEmitter.php
index ea321977..e576232d 100644
--- a/src/SwooleEmitter.php
+++ b/src/SwooleEmitter.php
@@ -100,7 +100,7 @@ private function emitBody(ResponseInterface $response) : void
     private function emitCookies(ResponseInterface $response) : void
     {
         foreach (SetCookies::fromResponse($response)->getAll() as $cookie) {
-            $sameSite = $cookie->getSameSite() ? substr($cookie->getSameSite()->asString(), 9) : null;
+            $sameSite = $cookie->getSameSite() ? substr($cookie->getSameSite()->asString(), 9) : '';
 
             $this->swooleResponse->cookie(
                 $cookie->getName(),
diff --git a/test/SwooleEmitterTest.php b/test/SwooleEmitterTest.php
index 0b8d5180..cc604e7e 100644
--- a/test/SwooleEmitterTest.php
+++ b/test/SwooleEmitterTest.php
@@ -94,13 +94,13 @@ public function testMultipleSetCookieHeaders()
             ->header('Set-Cookie', Argument::any())
             ->shouldNotBeCalled();
         $this->swooleResponse
-            ->cookie('foo', 'bar', 0, '/', '', false, false, null)
+            ->cookie('foo', 'bar', 0, '/', '', false, false, '')
             ->shouldHaveBeenCalled();
         $this->swooleResponse
-            ->cookie('bar', 'baz', 0, '/', '', false, false, null)
+            ->cookie('bar', 'baz', 0, '/', '', false, false, '')
             ->shouldHaveBeenCalled();
         $this->swooleResponse
-            ->cookie('baz', 'qux', 1623233894, '/', 'somecompany.co.uk', true, true, null)
+            ->cookie('baz', 'qux', 1623233894, '/', 'somecompany.co.uk', true, true, '')
             ->shouldHaveBeenCalled();
 
         // SameSite cookies