Add phpunit tool.

composer.json

@@ -17,11 +17,18 @@
 	"require": {
 		"php": ">=7.1",
 		"guzzlehttp/guzzle": "^6.2",
-		"nicmart/string-template": "~0.1"
+		"nicmart/string-template": "~0.1",
+		"mockery/mockery": "0.9.*",
+		"phpunit/phpunit": "~6.0"
 	},
 	"autoload": {
 		"psr-4": {
 			"AnomalyLab\\LuminousSMS\\": "src/"
 		}
+	},
+	"autoload-dev": {
+		"psr-4": {
+			"AnomalyLab\\LuminousSMS\\Tests\\": "tests/"
+		}
 	}
 }

phpunit.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         syntaxCheck="false">
+    <testsuites>
+        <testsuite name="Application Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory suffix=".php">src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>

tests/TestCase.php

@@ -0,0 +1,19 @@
+<?php
+
+use AnomalyLab\LuminousSMS\Tests;
+
+use Mockery;
+use PHPUnit\Framework\TestCase as PHPUnitTestCase;
+
+class TestCase extends PHPUnitTestCase
+{
+	public function setUp()
+	{
+		Mockery::globalHelpers();
+	}
+
+	public function tearDown()
+	{
+		Mockery::close();
+	}
+}