diff --git a/tests/Io/HttpBodyStreamTest.php b/tests/Io/HttpBodyStreamTest.php
index ad0a9131..343a75a5 100644
--- a/tests/Io/HttpBodyStreamTest.php
+++ b/tests/Io/HttpBodyStreamTest.php
@@ -88,12 +88,12 @@ public function testToString()
 
     public function testDetach()
     {
-        $this->assertEquals(null, $this->bodyStream->detach());
+        $this->assertNull($this->bodyStream->detach());
     }
 
     public function testGetSizeDefault()
     {
-        $this->assertEquals(null, $this->bodyStream->getSize());
+        $this->assertNull($this->bodyStream->getSize());
     }
 
     public function testGetSizeCustom()
@@ -146,7 +146,7 @@ public function testGetContents()
 
     public function testGetMetaData()
     {
-        $this->assertEquals(null, $this->bodyStream->getMetadata());
+        $this->assertNull($this->bodyStream->getMetadata());
     }
 
     public function testIsReadable()
diff --git a/tests/Io/MultipartParserTest.php b/tests/Io/MultipartParserTest.php
index 30dbcf99..3a034afb 100644
--- a/tests/Io/MultipartParserTest.php
+++ b/tests/Io/MultipartParserTest.php
@@ -593,7 +593,7 @@ public function testInvalidUploadFileWithoutContentTypeUsesNullValue()
         $file = $files['file'];
 
         $this->assertSame('hello.txt', $file->getClientFilename());
-        $this->assertSame(null, $file->getClientMediaType());
+        $this->assertNull($file->getClientMediaType());
         $this->assertSame(5, $file->getSize());
         $this->assertSame(UPLOAD_ERR_OK, $file->getError());
         $this->assertSame('world', (string)$file->getStream());
diff --git a/tests/Io/ServerRequestTest.php b/tests/Io/ServerRequestTest.php
index 9c04a4ea..b9fc8444 100644
--- a/tests/Io/ServerRequestTest.php
+++ b/tests/Io/ServerRequestTest.php
@@ -40,7 +40,7 @@ public function testGetDefaultAttribute()
         $request = $this->request->withAttribute('hello', 'world');
 
         $this->assertNotSame($request, $this->request);
-        $this->assertEquals(null, $request->getAttribute('hi', null));
+        $this->assertNull($request->getAttribute('hi', null));
     }
 
     public function testWithoutAttribute()
diff --git a/tests/StreamingServerTest.php b/tests/StreamingServerTest.php
index 69868437..3396c227 100644
--- a/tests/StreamingServerTest.php
+++ b/tests/StreamingServerTest.php
@@ -191,7 +191,7 @@ public function testRequestGetWithHostAndDefaultPortWillBeIgnored()
         $this->assertSame('/', $requestAssertion->getRequestTarget());
         $this->assertSame('/', $requestAssertion->getUri()->getPath());
         $this->assertSame('http://example.com/', (string)$requestAssertion->getUri());
-        $this->assertSame(null, $requestAssertion->getUri()->getPort());
+        $this->assertNull($requestAssertion->getUri()->getPort());
         $this->assertSame('example.com', $requestAssertion->getHeaderLine('Host'));
     }
 
@@ -290,7 +290,7 @@ public function testRequestConnectAuthorityFormWithDefaultPortWillBeIgnored()
         $this->assertSame('example.com:80', $requestAssertion->getRequestTarget());
         $this->assertSame('', $requestAssertion->getUri()->getPath());
         $this->assertSame('http://example.com', (string)$requestAssertion->getUri());
-        $this->assertSame(null, $requestAssertion->getUri()->getPort());
+        $this->assertNull($requestAssertion->getUri()->getPort());
         $this->assertSame('example.com', $requestAssertion->getHeaderLine('Host'));
     }
 
@@ -312,7 +312,7 @@ public function testRequestConnectAuthorityFormNonMatchingHostWillBeOverwritten(
         $this->assertSame('example.com:80', $requestAssertion->getRequestTarget());
         $this->assertSame('', $requestAssertion->getUri()->getPath());
         $this->assertSame('http://example.com', (string)$requestAssertion->getUri());
-        $this->assertSame(null, $requestAssertion->getUri()->getPort());
+        $this->assertNull($requestAssertion->getUri()->getPort());
         $this->assertSame('example.com', $requestAssertion->getHeaderLine('Host'));
     }