diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6147152
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/vendor
+/composer.lock
+/.phpunit.*
\ No newline at end of file
diff --git a/composer.json b/composer.json
index cbbc3dc..5c3308e 100644
--- a/composer.json
+++ b/composer.json
@@ -27,10 +27,16 @@
     },
     "minimum-stability": "dev",
     "prefer-stable": true,
-    "version": "1.0.0",
+    "version": "1.0.1",
     "extra": {
         "branch-alias": {
             "dev-master": "1.0.x-dev"
         }
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^9"
+    },
+    "scripts": {
+        "test": "vendor/bin/phpunit --testdox -c phpunit.xml"
     }
 }
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..4e0fe07
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- http://phpunit.de/manual/4.1/en/appendixes.configuration.html -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+>
+  <testsuites>
+    <testsuite name="">
+      <directory>./src/tests</directory>
+    </testsuite>
+  </testsuites>
+
+  <php>
+    <env name="RMS_MERCHANT_ID" value="SB_sandbox"/>
+    <env name="RMS_VERIFY_KEY" value="--replaceme--"/>
+    <env name="RMS_SECRET_KEY" value="--replaceme---"/>
+    <env name="RMS_ENVIRONMENT" value="sandbox"/>
+    <env name="DEBUG" value="false"/>
+  </php>
+</phpunit>
\ No newline at end of file
diff --git a/src/lib/Payment.php b/src/lib/Payment.php
index 0f429e4..555fbc5 100644
--- a/src/lib/Payment.php
+++ b/src/lib/Payment.php
@@ -20,6 +20,7 @@ public function __construct($merchantId, $verifyKey, $secretKey, $environment)
 
     public function getPaymentUrl($orderid, $amount, $bill_name, $bill_email, $bill_mobile, $bill_desc = 'RMS PHP Library', $channel = null, $currency = null, $returnUrl = null, $callbackurl = null, $cancelurl = null)
     {
+        $amount = number_format($amount, 2, '.', '');
         $data = [
             'orderid' => $orderid,
             'amount' => $amount,
diff --git a/src/support/helpers.php b/src/support/helpers.php
new file mode 100644
index 0000000..b7162ca
--- /dev/null
+++ b/src/support/helpers.php
@@ -0,0 +1,25 @@
+<?php
+
+if (! function_exists("env")) {
+    function env($key, $default = null) {
+        $envval = getenv($key);
+        if (empty($envval)) {
+            return null;
+        }
+        return $envval;
+    }
+}
+
+if (! function_exists("dump")) {
+    function dump($val) {
+        fwrite(STDERR, print_r($val, 1) . PHP_EOL);
+    }
+}
+
+if (! function_exists("writelog")) {
+    function writelog($val, $level = "INFO", $extras = null) {
+        if (env("DEBUG", false)) {
+            dump("↓↓ [$level] $val ".(isset($extras) ? json_encode($extras) : ""));
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/tests/PackageTest.php b/src/tests/PackageTest.php
new file mode 100644
index 0000000..a25bd6b
--- /dev/null
+++ b/src/tests/PackageTest.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+require_once(__DIR__."/../support/helpers.php");
+
+use PHPUnit\Framework\TestCase;
+use RazerMerchantServices\Payment as RmsPayment;
+
+final class PackageTest extends TestCase
+{
+    public function testCanDiscoverThisPackage(): void
+    {
+        $this->assertTrue(
+            class_exists(RmsPayment::class)
+        );
+    }
+
+    /**
+     * @depends testCanDiscoverThisPackage
+     */
+    public function testCanInstantateBaseClass(): void
+    {
+        $rms = new RmsPayment(null, null, null, null);
+
+        $this->assertNotNull($rms);
+        $this->assertEquals(get_class($rms), RmsPayment::class);
+    }
+}
\ No newline at end of file
diff --git a/src/tests/PaymentTest.php b/src/tests/PaymentTest.php
new file mode 100644
index 0000000..91a3333
--- /dev/null
+++ b/src/tests/PaymentTest.php
@@ -0,0 +1,148 @@
+<?php declare(strict_types=1);
+
+require_once(__DIR__."/../support/helpers.php");
+
+use PHPUnit\Framework\TestCase;
+use RazerMerchantServices\Payment as RmsPayment;
+
+final class PaymentTest extends TestCase
+{
+    private static $orderid = null;
+    private static $amount = null;
+    private static $bill_name = null;
+    private static $bill_email = null;
+    private static $bill_mobile = null;
+    private static $logbuf = [];
+
+    public static function setupBeforeClass(): void
+    {
+        self::$orderid = "TEST-ORDER";
+        self::$amount = "1.10";
+        self::$bill_name = "TEST USER";
+        self::$bill_email = "test@phpunit.com";
+        self::$bill_mobile = "+60123456789";
+    }
+
+    public function testCanHandleInstantiationErrors(): RmsPayment
+    {
+        $rms = new RmsPayment(env('RMS_MERCHANT_ID'), env('RMS_VERIFY_KEY'), env('RMS_SECRET_KEY'), env('RMS_ENVIRONMENT'));
+        
+        $this->assertEquals(
+            RmsPayment::class,
+            get_class($rms)
+        );
+
+        // TODO: add handling for invalid instantiations
+        //       and then test the errors here
+        // $this->expectException(InvalidArgumentException::class);
+
+        return $rms;
+    }
+
+    /**
+     * @depends testCanHandleInstantiationErrors
+     */
+    public function testCanCreatePaymentLink(RmsPayment $rms): string
+    {
+        $url = $rms->getPaymentUrl(
+            self::$orderid, 
+            self::$amount, 
+            self::$bill_name, 
+            self::$bill_email, 
+            self::$bill_mobile
+        );
+
+        writelog("Url - $url");
+        // check payment type
+        $this->assertIsString($url);
+
+        // check url must start with https://
+        $this->assertStringStartsWith("https://", $url);
+
+        // check domain must be pointing to correct endpoint
+        if (env("RMS_ENVIRONMENT") == "sandbox") {
+            $this->assertStringStartsWith("https://sandbox.merchant.razer.com", $url);
+        } else {
+            $this->assertStringStartsWith("https://pay.merchant.razer.com", $url);
+        }
+
+        return $url;
+    }
+
+    /**
+     * @depends testCanCreatePaymentLink
+     */
+    public function testUrlContainsRequiredParameters(string $url): string
+    {
+        // check url must contain required parameters
+        $this->assertStringContainsString("orderid=".self::$orderid, $url);
+        $this->assertStringContainsString("amount=".self::$amount, $url);
+        $this->assertStringContainsString("bill_name=".urlencode(self::$bill_name), $url);
+        $this->assertStringContainsString("bill_email=".urlencode(self::$bill_email), $url);
+        $this->assertStringContainsString("bill_mobile=".urlencode(self::$bill_mobile), $url);
+        $this->assertStringContainsString("bill_desc=".urlencode("RMS PHP Library"), $url);
+
+        return $url;
+    }
+
+    /**
+     * @depends testUrlContainsRequiredParameters
+     */
+    public function testVcodeIsProperlyCalculated(string $url): void
+    {
+        $amount = number_format(self::$amount*1, 2, '.', '');
+        writelog("Amount: $amount");
+        $calculatedVcode = md5($amount . env('RMS_MERCHANT_ID') . self::$orderid . env('RMS_VERIFY_KEY'));
+        writelog("Calculated Vcode - $calculatedVcode");
+        // check url contains valid vcode
+        $this->assertStringContainsString("&vcode=$calculatedVcode", $url);
+    }
+
+    /**
+     * @depends testCanHandleInstantiationErrors
+     */
+    public function testCanVerifyValidSkey($rms) : void
+    {
+        $request = (object)[
+            "tranID" => 1000,
+            "amount" => "1.10",
+            "orderid" => "TEST-ORDER",
+            "status" => "00",
+            "currency" => "MYR",
+            "paydate" => date("Ymd H:i:s"),
+            "domain" => env("RMS_MERCHANT_ID"),
+            "appcode" => "123456",
+        ];
+
+        $key = md5($request->tranID.$request->orderid.$request->status.$request->domain.$request->amount.$request->currency);
+        $request->skey = md5($request->paydate.$request->domain.$key.$request->appcode.env('RMS_SECRET_KEY'));
+
+        $this->assertTrue(
+            $rms->verifySignature($request->paydate, $request->domain, $key, $request->appcode, $request->skey)
+        );
+    }
+
+    /**
+     * @depends testCanHandleInstantiationErrors
+     */
+    public function testCanVerifyInvalidSkey($rms) : void
+    {
+        $request = (object)[
+            "tranID" => 1000,
+            "amount" => "1.10",
+            "orderid" => "TEST-ORDER",
+            "status" => "00",
+            "currency" => "MYR",
+            "paydate" => date("Ymd H:i:s"),
+            "domain" => env("RMS_MERCHANT_ID"),
+            "appcode" => "123456",
+        ];
+
+        $key = md5($request->tranID.$request->orderid.$request->status.$request->domain.$request->amount.$request->currency);
+        $request->skey = "just-a-tampered-skey";
+
+        $this->assertNotTrue(
+            $rms->verifySignature($request->paydate, $request->domain, $key, $request->appcode, $request->skey)
+        );
+    }
+}