diff --git a/.travis.yml b/.travis.yml
index f3b5e35..4f44c9a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,9 @@
 language: php
+dist: trusty
 php:
+  - "7.4"
+  - "7.3"
+  - "7.2"
   - "7.1"
   - "7.0"
   - "5.6"
diff --git a/composer.json b/composer.json
index f2afa34..a8dc1ab 100644
--- a/composer.json
+++ b/composer.json
@@ -1,21 +1,29 @@
 {
-    "name": "codemix/yii2-configloader",
-    "description": "Build configuration arrays from config files and env vars.",
-    "keywords": ["yii2", "config", "environment"],
-    "license": "MIT",
-    "authors": [
-        {
-            "name": "Michael Härtl",
-            "email": "haertl.mike@gmail.com"
-        }
-    ],
-    "require": {
-      "yiisoft/yii2": "*",
-      "vlucas/phpdotenv": "2.5.*"
-    },
-    "autoload": {
-        "psr-4": {
-            "codemix\\yii2confload\\": "src/"
-        }
+  "name": "codemix/yii2-configloader",
+  "description": "Build configuration arrays from config files and env vars.",
+  "keywords": ["yii2", "config", "environment"],
+  "license": "MIT",
+  "authors": [
+    {
+      "name": "Michael Härtl",
+      "email": "haertl.mike@gmail.com"
     }
+  ],
+  "require": {
+    "yiisoft/yii2": "*",
+    "vlucas/phpdotenv": "2.5.*"
+  },
+  "require-dev": {
+    "phpunit/phpunit": ">4.0 <8"
+  },
+  "autoload": {
+    "psr-4": {
+      "codemix\\yii2confload\\": "src/"
+    }
+  },
+  "autoload-dev": {
+      "psr-4": {
+          "tests\\": "tests"
+      }
+  }
 }
diff --git a/tests/BootstrapTest.php b/tests/BootstrapTest.php
index 8b4ebec..42c21e6 100644
--- a/tests/BootstrapTest.php
+++ b/tests/BootstrapTest.php
@@ -1,7 +1,10 @@
 <?php
+namespace tests;
+
+use \PHPUnit\Framework\TestCase;
 use codemix\yii2confload\Config;
 
-class BootstrapTest extends \PHPUnit\Framework\TestCase
+class BootstrapTest extends TestCase
 {
     public function testCanBootstrapApplication()
     {
diff --git a/tests/ConsoleConfigTest.php b/tests/ConsoleConfigTest.php
index fd2cddd..0ccc1c3 100644
--- a/tests/ConsoleConfigTest.php
+++ b/tests/ConsoleConfigTest.php
@@ -1,7 +1,10 @@
 <?php
+namespace tests;
+
+use \PHPUnit\Framework\TestCase;
 use codemix\yii2confload\Config;
 
-class ConsoleConfigTest extends \PHPUnit\Framework\TestCase
+class ConsoleConfigTest extends TestCase
 {
     public function testCanGetConfig()
     {
diff --git a/tests/EnvTest.php b/tests/EnvTest.php
index 84ee6ed..e864485 100644
--- a/tests/EnvTest.php
+++ b/tests/EnvTest.php
@@ -1,7 +1,10 @@
 <?php
+namespace tests;
+
+use \PHPUnit\Framework\TestCase;
 use codemix\yii2confload\Config;
 
-class EnvTest extends \PHPUnit\Framework\TestCase
+class EnvTest extends TestCase
 {
     public function testCanInitYiiEnvFromEnvVars()
     {
diff --git a/tests/WebConfigTest.php b/tests/WebConfigTest.php
index 75438b4..67b9a49 100644
--- a/tests/WebConfigTest.php
+++ b/tests/WebConfigTest.php
@@ -1,7 +1,10 @@
 <?php
+namespace tests;
+
+use \PHPUnit\Framework\TestCase;
 use codemix\yii2confload\Config;
 
-class WebConfigTest extends \PHPUnit\Framework\TestCase
+class WebConfigTest extends TestCase
 {
     public function testCanGetConfig()
     {