diff --git a/src/Support/Arr.php b/src/Support/Arr.php
new file mode 100644
index 0000000..dc8426e
--- /dev/null
+++ b/src/Support/Arr.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Creagia\Redsys\Support;
+
+use Countable;
+use Stringable;
+
+class Arr
+{
+    /**
+     * Determine if the given value is "blank".
+     * https://github.com/laravel/framework/blob/11.x/src/Illuminate/Support/helpers.php#L49
+     *
+     * @phpstan-assert-if-false !=null|'' $value
+     *
+     * @phpstan-assert-if-true !=numeric|bool $value
+     *
+     * @param  mixed  $value
+     * @return bool
+     */
+    public static function blank(mixed $value): bool
+    {
+        if (is_null($value)) {
+            return true;
+        }
+
+        if (is_string($value)) {
+            return trim($value) === '';
+        }
+
+        if (is_numeric($value) || is_bool($value)) {
+            return false;
+        }
+
+        if ($value instanceof Countable) {
+            return count($value) === 0;
+        }
+
+        if ($value instanceof Stringable) {
+            return trim((string) $value) === '';
+        }
+
+        return empty($value);
+    }
+
+    /**
+     * Determine if a value is "filled".
+     * https://github.com/laravel/framework/blob/11.x/src/Illuminate/Support/helpers.php#L164
+     *
+     * @phpstan-assert-if-true !=null|'' $value
+     *
+     * @phpstan-assert-if-false !=numeric|bool $value
+     *
+     * @param  mixed  $value
+     * @return bool
+     */
+    public static function filled(mixed $value): bool
+    {
+        return ! self::blank($value);
+    }
+}
diff --git a/src/Support/RequestParameters.php b/src/Support/RequestParameters.php
index fca83b2..0a2a0c3 100644
--- a/src/Support/RequestParameters.php
+++ b/src/Support/RequestParameters.php
@@ -218,6 +218,6 @@ public function toEncodedString(): string
 
     public function toArray(): array
     {
-        return array_filter(parent::toArray());
+        return array_filter(parent::toArray(), [Arr::class, 'filled']);
     }
 }
diff --git a/tests/ResponseTest.php b/tests/ResponseTest.php
index 97b9d8c..6771a06 100644
--- a/tests/ResponseTest.php
+++ b/tests/ResponseTest.php
@@ -1,55 +1,106 @@
 <?php
 
-beforeEach(function () {
-    $this->redsysClient = new \Creagia\Redsys\RedsysClient(
-        merchantCode: 123123,
-        secretKey: 123123,
-        terminal: 1,
-        environment: \Creagia\Redsys\Enums\Environment::Production,
-    );
-
-    $redsysRequest = \Creagia\Redsys\RedsysRequest::create(
-        $this->redsysClient,
-        new \Creagia\Redsys\Support\RequestParameters(
-            amountInCents: $this->paymentRequestAmount = 123_12,
-            order: 9999,
-            currency: \Creagia\Redsys\Enums\Currency::EUR,
-            transactionType: \Creagia\Redsys\Enums\TransactionType::Autorizacion,
-        )
-    );
-
-    $this->redsysFakeGateway = new \Creagia\Redsys\RedsysFakeGateway($redsysRequest->getRequestFieldsArray(), 123123);
-});
-
-it('can validate a valid signature', function () {
-    $responsePost = $this->redsysFakeGateway->getResponse('0000');
-
-    $redsysNotification = new \Creagia\Redsys\RedsysResponse($this->redsysClient);
+it('can validate a valid signature', function (
+    \Creagia\Redsys\RedsysClient $redsysClient,
+    int $paymentRequestAmount,
+    \Creagia\Redsys\RedsysFakeGateway $redsysFakeGateway
+) {
+    $responsePost = $redsysFakeGateway->getResponse('0000');
+
+    $redsysNotification = new \Creagia\Redsys\RedsysResponse($redsysClient);
     $redsysNotification->setParametersFromResponse($responsePost);
     $result = $redsysNotification->checkResponse();
 
-    expect($result->amount)->toBe($this->paymentRequestAmount);
-});
+    expect($result->amount)->toBe($paymentRequestAmount);
+})->with('gateway');
 
-it('fails if signatures differ', function () {
-    $responsePost = $this->redsysFakeGateway->getResponse('0000');
+it('fails if signatures differ', function (
+    \Creagia\Redsys\RedsysClient $redsysClient,
+    int $paymentRequestAmount,
+    \Creagia\Redsys\RedsysFakeGateway $redsysFakeGateway
+) {
+    $responsePost = $redsysFakeGateway->getResponse('0000');
     $responsePost['Ds_Signature'] = "123";
 
-    $redsysNotification = new \Creagia\Redsys\RedsysResponse($this->redsysClient);
+    $redsysNotification = new \Creagia\Redsys\RedsysResponse($redsysClient);
     $redsysNotification->setParametersFromResponse($responsePost);
     $redsysNotification->checkResponse();
-})->throws(\Creagia\Redsys\Exceptions\InvalidRedsysResponseException::class, 'does not match');
+})
+    ->with('gateway')
+    ->throws(\Creagia\Redsys\Exceptions\InvalidRedsysResponseException::class, 'does not match');
 
-it('throws an exception if invalid response from Redsys', function () {
-    $redsysNotification = new \Creagia\Redsys\RedsysResponse($this->redsysClient);
+it('throws an exception if invalid response from Redsys', function (
+    \Creagia\Redsys\RedsysClient $redsysClient,
+    int $paymentRequestAmount,
+    \Creagia\Redsys\RedsysFakeGateway $redsysFakeGateway
+) {
+    $redsysNotification = new \Creagia\Redsys\RedsysResponse($redsysClient);
     $redsysNotification->setParametersFromResponse([]);
     $redsysNotification->checkResponse();
-})->throws(\Creagia\Redsys\Exceptions\InvalidRedsysResponseException::class);
+})
+    ->with('gateway')
+    ->throws(\Creagia\Redsys\Exceptions\InvalidRedsysResponseException::class);
 
-it('throws an exception if denied response from Redsys', function () {
-    $responsePost = $this->redsysFakeGateway->getResponse('0184');
+it('throws an exception if denied response from Redsys', function (
+    \Creagia\Redsys\RedsysClient $redsysClient,
+    int $paymentRequestAmount,
+    \Creagia\Redsys\RedsysFakeGateway $redsysFakeGateway
+) {
+    $responsePost = $redsysFakeGateway->getResponse('0184');
 
-    $redsysNotification = new \Creagia\Redsys\RedsysResponse($this->redsysClient);
+    $redsysNotification = new \Creagia\Redsys\RedsysResponse($redsysClient);
     $redsysNotification->setParametersFromResponse($responsePost);
     $redsysNotification->checkResponse();
-})->throws(\Creagia\Redsys\Exceptions\DeniedRedsysPaymentResponseException::class);
+})
+    ->with('gateway')
+    ->throws(\Creagia\Redsys\Exceptions\DeniedRedsysPaymentResponseException::class);
+
+$redsysClient = new \Creagia\Redsys\RedsysClient(
+    merchantCode: 123123,
+    secretKey: 123123,
+    terminal: 1,
+    environment: \Creagia\Redsys\Enums\Environment::Production,
+);
+
+dataset('gateway', [
+    [
+        $redsysClient,
+        $paymentRequestAmount = 123_12,
+        function () use ($redsysClient, $paymentRequestAmount) {
+            $redsysRequest = \Creagia\Redsys\RedsysRequest::create(
+                $redsysClient,
+                new \Creagia\Redsys\Support\RequestParameters(
+                    amountInCents: $paymentRequestAmount,
+                    transactionType: \Creagia\Redsys\Enums\TransactionType::Autorizacion,
+                    currency: \Creagia\Redsys\Enums\Currency::EUR,
+                    order: 9999,
+                )
+            );
+
+            return $this->redsysFakeGateway = new \Creagia\Redsys\RedsysFakeGateway(
+                $redsysRequest->getRequestFieldsArray(),
+                123123
+            );
+        },
+    ],
+    [
+        $redsysClient,
+        $paymentRequestAmount = 0,
+        function () use ($redsysClient, $paymentRequestAmount) {
+            $redsysRequest = \Creagia\Redsys\RedsysRequest::create(
+                $redsysClient,
+                new \Creagia\Redsys\Support\RequestParameters(
+                    amountInCents: $paymentRequestAmount,
+                    transactionType: \Creagia\Redsys\Enums\TransactionType::Autorizacion,
+                    currency: \Creagia\Redsys\Enums\Currency::EUR,
+                    order: 9999,
+                )
+            );
+
+            return $this->redsysFakeGateway = new \Creagia\Redsys\RedsysFakeGateway(
+                $redsysRequest->getRequestFieldsArray(),
+                123123
+            );
+        },
+    ],
+]);