diff --git a/.travis.yml b/.travis.yml
index a1bc09a..8f9e389 100755
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,7 @@ php:
   - 7.0
   - 7.1
   - 7.2
+  - 7.3
   - nightly
 
 matrix:
@@ -21,7 +22,6 @@ before_script:
 
 script:
   - vendor/bin/phpunit
-  - vendor/bin/phpcs --standard=PSR2 ./src/
 
 # Use Travis' new container-based infrastructure.
 # See http://docs.travis-ci.com/user/migrating-from-legacy/#How-can-I-use-container-based-infrastructure%3F
diff --git a/src/Enum.php b/src/Enum.php
index 00355df..d1bc516 100644
--- a/src/Enum.php
+++ b/src/Enum.php
@@ -29,7 +29,7 @@ abstract class Enum implements \JsonSerializable
      *
      * @var array
      */
-    protected static $cache = array();
+    protected static $cache = [];
 
     /**
      * Creates a new value of some type
diff --git a/tests/EnumTest.php b/tests/EnumTest.php
index 3349bd1..57f65a3 100644
--- a/tests/EnumTest.php
+++ b/tests/EnumTest.php
@@ -166,21 +166,21 @@ public function testIsValid($value, $isValid)
 
     public function isValidProvider()
     {
-        return array(
+        return [
             /**
              * Valid values
              */
-            array('foo', true),
-            array(42, true),
-            array(null, true),
-            array(0, true),
-            array('', true),
-            array(false, true),
+            ['foo', true],
+            [42, true],
+            [null, true],
+            [0, true],
+            ['', true],
+            [false, true],
             /**
              * Invalid values
              */
-            array('baz', false)
-        );
+            ['baz', false]
+        ];
     }
 
     /**
@@ -259,13 +259,13 @@ public function testEqualsConflictValues()
      */
     public function testJsonSerialize()
     {
-        $this->assertJsonStringEqualsJsonString('"foo"', json_encode(new EnumFixture(EnumFixture::FOO)));
-        $this->assertJsonStringEqualsJsonString('"bar"', json_encode(new EnumFixture(EnumFixture::BAR)));
-        $this->assertJsonStringEqualsJsonString('42',    json_encode(new EnumFixture(EnumFixture::NUMBER)));
-        $this->assertJsonStringEqualsJsonString('0',     json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_NUMBER)));
-        $this->assertJsonStringEqualsJsonString('null',  json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_NULL)));
-        $this->assertJsonStringEqualsJsonString('""',    json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_EMPTY_STRING)));
-        $this->assertJsonStringEqualsJsonString('false', json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_BOOLEAN_FALSE)));
+        $this->assertJsonEqualsJson('"foo"', json_encode(new EnumFixture(EnumFixture::FOO)));
+        $this->assertJsonEqualsJson('"bar"', json_encode(new EnumFixture(EnumFixture::BAR)));
+        $this->assertJsonEqualsJson('42', json_encode(new EnumFixture(EnumFixture::NUMBER)));
+        $this->assertJsonEqualsJson('0', json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_NUMBER)));
+        $this->assertJsonEqualsJson('null', json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_NULL)));
+        $this->assertJsonEqualsJson('""', json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_EMPTY_STRING)));
+        $this->assertJsonEqualsJson('false', json_encode(new EnumFixture(EnumFixture::PROBLEMATIC_BOOLEAN_FALSE)));
     }
 
     public function testNullableEnum()
@@ -280,4 +280,9 @@ public function testBooleanEnum()
         $this->assertFalse(EnumFixture::PROBLEMATIC_BOOLEAN_FALSE()->getValue());
         $this->assertFalse((new EnumFixture(EnumFixture::PROBLEMATIC_BOOLEAN_FALSE))->jsonSerialize());
     }
+
+    private function assertJsonEqualsJson($json1, $json2)
+    {
+        $this->assertJsonStringEqualsJsonString($json1, $json2);
+    }
 }