diff --git a/.gitignore b/.gitignore
index 3a9875b..103e692 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 /vendor/
 composer.lock
+.phpunit.result.*
+build/
diff --git a/README.md b/README.md
index d5d3cc3..c885570 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,11 @@ But at the same time you still WANT to implement **good practices** and **standa
     --standard The name or path of the coding standard. Defaults to PSR12.
 ```
 
+## Run tests
+```
+$ composer test
+```
+
 ### License
 
 ```
diff --git a/bin/super-giggle b/bin/super-giggle
index 2fc4242..bd44f12 100755
--- a/bin/super-giggle
+++ b/bin/super-giggle
@@ -19,10 +19,12 @@ if (file_exists(__DIR__ . '/../vendor/autoload.php') === true) {
 use SuperGiggle\Main;
 use SuperGiggle\Util;
 
-$opts = Util::parseArgs();
+$util = new Util;
+$opts = $util->parseArgs();
 if (isset($opts['help'])) {
-    Util::printUsage();
+    $util->printUsage();
 }
 
 $phpcs = new Main();
+$phpcs->setUtil($util);
 $phpcs->run($opts);
diff --git a/composer.json b/composer.json
index 3aa20f4..a164760 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,13 @@
 {
     "autoload": {
-        "psr-4": {"SuperGiggle\\": "src/"}
+        "psr-4": {
+            "SuperGiggle\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "SuperGiggle\\": "tests/src/"
+        }
     },
     "name": "roger-sei/super-giggle",
     "description": "SuperGiggle checks the coding standards for a specific commit change",
@@ -11,5 +18,11 @@
     "license": "MIT",
     "bin": [
         "bin/super-giggle"
-    ]
+    ],
+    "require-dev": {
+        "phpunit/phpunit": "^8"
+    },
+    "scripts": {
+        "test": "phpunit --testdox --colors=always"
+    }
 }
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..ff5edb5
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit bootstrap="vendor/autoload.php"
+         backupGlobals="false"
+         backupStaticAttributes="false"
+         colors="true"
+         verbose="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false">
+    <testsuites>
+        <testsuite name="SupperGiggle Test Suite">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory suffix=".php">src/</directory>
+        </whitelist>
+    </filter>
+    <logging>
+        <log type="tap" target="build/report.tap"/>
+        <log type="junit" target="build/report.junit.xml"/>
+        <log type="coverage-html" target="build/coverage" lowUpperBound="35" highLowerBound="70"/>
+        <log type="coverage-text" target="build/coverage.txt"/>
+        <log type="coverage-clover" target="build/logs/clover.xml"/>
+    </logging>
+</phpunit>
diff --git a/src/Main.php b/src/Main.php
index b97826a..eb7afdf 100644
--- a/src/Main.php
+++ b/src/Main.php
@@ -16,8 +16,6 @@
 
 namespace SuperGiggle;
 
-use SuperGiggle\Util;
-
 class Main
 {
 
@@ -42,6 +40,13 @@ class Main
      */
     private $options = [];
 
+    /**
+     * Util class
+     *
+     * @var Util
+     */
+    private $util;
+
     /**
      * Indicates whether it has found error or not.
      *
@@ -68,6 +73,19 @@ public function __construct()
     }
 
 
+    /**
+     * Set util class.
+     *
+     * @param Util $util Util class.
+     *
+     * @return void
+     */
+    public function setUtil(Util $util): void
+    {
+        $this->util = $util;
+    }
+
+
     /**
      * Helper to display a message and exit.
      *
@@ -196,7 +214,7 @@ private function parsePHPCSErrors(string $file): array
         $phpcs      = $this->options['phpcs'];
         $warnings   = $this->options['warnings'];
         $phpVersion = (empty($this->options['php-version']) === true) ? '' : "--runtime-set php_version {$this->options['php-version']}";
-        $execString = (Util::isWindows() === true) ? "$phpcs --report=json --standard=$stndr $file $warnings" :
+        $execString = ($this->util->isWindows() === true) ? "$phpcs --report=json --standard=$stndr $file $warnings" :
             "$php $phpcs --report=json --standard=$stndr '$file' $warnings $phpVersion";
 
         $response = shell_exec($execString);
diff --git a/src/Os.php b/src/Os.php
new file mode 100644
index 0000000..9b4a55a
--- /dev/null
+++ b/src/Os.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace SuperGiggle;
+
+class Os
+{
+
+    
+    /**
+     * Is the current platform windows?
+     *
+     * @return boolean
+     */
+    public function isWindows()
+    {
+        return (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
+    }
+
+
+}
diff --git a/src/Util.php b/src/Util.php
index 9f27400..499500c 100644
--- a/src/Util.php
+++ b/src/Util.php
@@ -19,13 +19,20 @@
 class Util
 {
 
+    /**
+     * Os util
+     *
+     * @var Os
+     */
+    private $os;
+
 
     /**
      * Parse args and return in a friendly format
      *
      * @return array
      */
-    public static function parseArgs(): array
+    public function parseArgs(): array
     {
         $alloweds = [
             'commit::',
@@ -56,7 +63,7 @@ public static function parseArgs(): array
      *
      * @return void
      */
-    public static function printUsage(): void
+    public function printUsage(): void
     {
         echo "  Usage: \033[0;35msuper-giggle [--commit]\033[0m\n\n";
         $options = [
@@ -86,11 +93,11 @@ public static function printUsage(): void
      *
      * @return string
      */
-    public static function getPhpCsBinary(): string
+    public function getPhpCsBinary(): string
     {
         $path = __DIR__ . '/../vendor/bin/phpcs';
 
-        if (self::isWindows() === true) {
+        if ($this->os->isWindows() === true) {
             $path = str_replace('\\', '/', __DIR__ . '/../vendor/bin/phpcs.bat');
         }
 
@@ -99,13 +106,15 @@ public static function getPhpCsBinary(): string
 
 
     /**
-     * Checks the OS and returns true if Windows system is found.
+     * Set current operating system.
+     *
+     * @param Os $os Os class.
      *
-     * @return boolean
+     * @return void
      */
-    public static function isWindows(): bool
+    public function setOs(Os $os): void
     {
-        return (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
+        $this->os = $os;
     }
 
 
diff --git a/tests/src/MainTest.php b/tests/src/MainTest.php
new file mode 100644
index 0000000..e69de29
diff --git a/tests/src/UtilTest.php b/tests/src/UtilTest.php
new file mode 100644
index 0000000..1210bce
--- /dev/null
+++ b/tests/src/UtilTest.php
@@ -0,0 +1,63 @@
+<?php
+
+namespace SuperGiggle;
+
+use PHPUnit\Framework\TestCase;
+
+class UtilTest extends TestCase
+{
+
+
+    /**
+     * Define if the object can be constructed
+     *
+     * @test
+     *
+     * @return void
+     */
+    public function objectCanBeConstructed()
+    {
+        $util = new Util();
+        $this->assertInstanceOf(Util::class, $util);
+    }
+
+
+    /**
+     * Test if directory is ok to windows platform
+     *
+     * @test
+     *
+     * @return void
+     */
+    public function phpCsBinaryOnWindows()
+    {
+        $os = $this->createMock(Os::class);
+        $os->method('isWindows')
+           ->willReturn(true);
+
+        $util = new Util();
+        $util->setOs($os);
+
+        $this->assertStringContainsString('/../vendor/bin/phpcs.bat', $util->getPhpCsBinary());
+    }
+    
+
+    /**
+     * Test if directory is ok to linux platform
+     *
+     * @test
+     *
+     * @return void
+     */
+    public function phpCsBinaryOnLinux()
+    {
+        $os = $this->createMock(Os::class);
+
+        $util = new Util();
+        $util->setOs($os);
+
+        $this->assertStringContainsString('/../vendor/bin/phpcs', $util->getPhpCsBinary());
+    }
+
+
+}