diff --git a/includes/AdminWidget.php b/includes/AdminWidget.php
index 0c166f9..dd4df8f 100644
--- a/includes/AdminWidget.php
+++ b/includes/AdminWidget.php
@@ -2,17 +2,17 @@
 
 namespace lloc\Nowpayments;
 
-use lloc\Nowpayments\Integration\ApiStatus;
+use lloc\Nowpayments\Integration\ApiStatusInterface;
 
 class AdminWidget {
 
 	public const WIDGET_ID = 'nowpayments_status_widget';
 
 	public function __construct(
-		protected readonly ApiStatus $status
+		protected readonly ApiStatusInterface $status
 	) { }
 
-	public static function create( ApiStatus $status ): AdminWidget {
+	public static function create( ApiStatusInterface $status ): AdminWidget {
 		$obj = new self( $status );
 
 		$widget_name = __( 'Nowpayments Status', 'wp-nowpayments-integration' );
@@ -23,12 +23,12 @@ public static function create( ApiStatus $status ): AdminWidget {
 	}
 
 	public function render(): void {
-		$arr     = $this->status->get();
+		$message = $this->status->get()['message'] ?? '';
 		$service = sprintf( '<strong>%s</strong>', $this->status->get_client()->get_service()->info() );
 
 		/* translators: 1: service name, 2: message */
 		$format = __( '%1$s responds with "%2$s".', 'wp-nowpayments-integration' );
 
-		echo wp_kses_post( '<div>' . sprintf( $format, $service, $arr['message'] ) . '</div>' );
+		echo wp_kses_post( '<div>' . sprintf( $format, $service, $message ) . '</div>' );
 	}
 }
diff --git a/includes/Integration/ApiStatus.php b/includes/Integration/ApiStatus.php
index 6618480..d956314 100644
--- a/includes/Integration/ApiStatus.php
+++ b/includes/Integration/ApiStatus.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class ApiStatus extends Endpoint {
+final class ApiStatus extends Endpoint implements ApiStatusInterface {
 
 	/**
 	 * @return string[]
diff --git a/includes/Integration/ApiStatusInterface.php b/includes/Integration/ApiStatusInterface.php
new file mode 100644
index 0000000..9d61e6d
--- /dev/null
+++ b/includes/Integration/ApiStatusInterface.php
@@ -0,0 +1,14 @@
+<?php declare( strict_types=1 );
+
+namespace lloc\Nowpayments\Integration;
+
+use lloc\Nowpayments\Rest\EndpointInterface;
+
+interface ApiStatusInterface extends EndpointInterface {
+
+
+	/**
+	 * @return string[]
+	 */
+	public function get(): array;
+}
diff --git a/includes/Integration/AvailableCurrencies.php b/includes/Integration/AvailableCurrencies.php
index 1d6ea98..b75e3fd 100644
--- a/includes/Integration/AvailableCurrencies.php
+++ b/includes/Integration/AvailableCurrencies.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class AvailableCurrencies extends Endpoint {
+final class AvailableCurrencies extends Endpoint {
 
 	/**
 	 * @return array<string, string[]>
diff --git a/includes/Integration/EstimatedPrice.php b/includes/Integration/EstimatedPrice.php
index b4810b3..8b60646 100644
--- a/includes/Integration/EstimatedPrice.php
+++ b/includes/Integration/EstimatedPrice.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class EstimatedPrice extends Endpoint {
+final class EstimatedPrice extends Endpoint {
 
 	/**
 	 * @param float  $amount
diff --git a/includes/Integration/MinimumPaymentAmount.php b/includes/Integration/MinimumPaymentAmount.php
index 270df0f..1aaf6de 100644
--- a/includes/Integration/MinimumPaymentAmount.php
+++ b/includes/Integration/MinimumPaymentAmount.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class MinimumPaymentAmount extends Endpoint {
+final class MinimumPaymentAmount extends Endpoint {
 
 	/**
 	 * @param string $currency_from
diff --git a/includes/Integration/Payment.php b/includes/Integration/Payment.php
index a489903..cae4d32 100644
--- a/includes/Integration/Payment.php
+++ b/includes/Integration/Payment.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class Payment extends Endpoint {
+final class Payment extends Endpoint {
 
 	public const ADDITIONAL_PARAMS = array(
 		'pay_amount',
diff --git a/includes/Integration/PaymentStatus.php b/includes/Integration/PaymentStatus.php
index 65af3d2..719804e 100644
--- a/includes/Integration/PaymentStatus.php
+++ b/includes/Integration/PaymentStatus.php
@@ -4,7 +4,7 @@
 
 use lloc\Nowpayments\Rest\Endpoint;
 
-class PaymentStatus extends Endpoint {
+final class PaymentStatus extends Endpoint {
 
 	public const ENDPOINT = 'v1/payment';
 
diff --git a/includes/Rest/Client.php b/includes/Rest/Client.php
index 6b2fff1..2c18820 100644
--- a/includes/Rest/Client.php
+++ b/includes/Rest/Client.php
@@ -23,9 +23,9 @@ public function get_service(): Service {
 	 * @param string[] $body
 	 * @param string[] $headers
 	 *
-	 * @return Result
+	 * @return ResultInterface
 	 */
-	public function get( string $endpoint, array $body = array(), array $headers = array() ): Result {
+	public function get( string $endpoint, array $body = array(), array $headers = array() ): ResultInterface {
 		$url = add_query_arg( $body, $this->service->get( $endpoint ) );
 
 		if ( ! empty( $headers ) ) {
@@ -42,9 +42,9 @@ public function get( string $endpoint, array $body = array(), array $headers = a
 	 * @param string[] $body
 	 * @param string[] $headers
 	 *
-	 * @return Result
+	 * @return ResultInterface
 	 */
-	public function post( string $endpoint, array $body = array(), array $headers = array() ): Result {
+	public function post( string $endpoint, array $body = array(), array $headers = array() ): ResultInterface {
 		$url  = $this->service->get( $endpoint );
 		$args = array();
 
diff --git a/includes/Rest/EndpointInterface.php b/includes/Rest/EndpointInterface.php
new file mode 100644
index 0000000..9698949
--- /dev/null
+++ b/includes/Rest/EndpointInterface.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace lloc\Nowpayments\Rest;
+
+interface EndpointInterface {
+
+
+	/**
+	 * @return Client
+	 */
+	public function get_client(): Client;
+}
diff --git a/includes/Rest/Error.php b/includes/Rest/Error.php
index f321d69..055f83d 100644
--- a/includes/Rest/Error.php
+++ b/includes/Rest/Error.php
@@ -4,7 +4,7 @@
 
 use WP_Error;
 
-class Error implements Result {
+class Error implements ResultInterface {
 
 	/**
 	 * @param WP_Error $error
diff --git a/includes/Rest/MethodGetInterface.php b/includes/Rest/MethodGetInterface.php
new file mode 100644
index 0000000..549897b
--- /dev/null
+++ b/includes/Rest/MethodGetInterface.php
@@ -0,0 +1,12 @@
+<?php declare( strict_types=1 );
+
+namespace lloc\Nowpayments\Rest;
+
+interface MethodGetInterface {
+
+
+	/**
+	 * @return string[]
+	 */
+	public function get(): array;
+}
diff --git a/includes/Rest/Response.php b/includes/Rest/Response.php
index d00e541..ca48e8b 100644
--- a/includes/Rest/Response.php
+++ b/includes/Rest/Response.php
@@ -2,7 +2,7 @@
 
 namespace lloc\Nowpayments\Rest;
 
-class Response implements Result {
+class Response implements ResultInterface {
 
 	/**
 	 * @var string[]
diff --git a/includes/Rest/Result.php b/includes/Rest/ResultInterface.php
similarity index 82%
rename from includes/Rest/Result.php
rename to includes/Rest/ResultInterface.php
index c617678..6ab77e5 100644
--- a/includes/Rest/Result.php
+++ b/includes/Rest/ResultInterface.php
@@ -2,7 +2,7 @@
 
 namespace lloc\Nowpayments\Rest;
 
-interface Result {
+interface ResultInterface {
 
 	/**
 	 * @return string[]
diff --git a/tests/Integration/TestAvailableCurrencies.php b/tests/Integration/TestAvailableCurrencies.php
index 6597314..40a2665 100644
--- a/tests/Integration/TestAvailableCurrencies.php
+++ b/tests/Integration/TestAvailableCurrencies.php
@@ -14,6 +14,21 @@ class TestAvailableCurrencies extends LlocTestCase {
 
 	public const EXPECTED = array( 'currencies' => array( 'ada', 'btc', 'eur' ) );
 
+	/**
+	 * Test Setup
+	 *
+	 * @return void
+	 */
+	public function setUp(): void {
+		parent::setUp();
+
+		$response = \Mockery::mock( Response::class );
+		$response->shouldReceive( 'get' )->andReturn( self::EXPECTED );
+
+		$this->client = \Mockery::mock( Client::class );
+		$this->client->shouldReceive( 'get' )->andReturn( $response );
+	}
+
 	/**
 	 * Method demonstrates how AvailableCurrencies works
 	 *
@@ -28,32 +43,27 @@ public function test_get(): void {
 	}
 
 	/**
-	 * The is_available method looks a currency in the cached result-set up
+	 * Data provider for is_available method
 	 *
-	 * @return void
+	 * @return array<int, array<int, string|bool>>
 	 */
-	public function test_is_available(): void {
-		Functions\expect( 'wp_cache_get' )->atLeast()->once()->andReturn( self::EXPECTED );
-
-		$this->assertFalse( ( new AvailableCurrencies( $this->client ) )->is_available( 'bch' ) );
-		$this->assertTrue( ( new AvailableCurrencies( $this->client ) )->is_available( 'ada' ) );
-		$this->assertTrue( ( new AvailableCurrencies( $this->client ) )->is_available( 'btc' ) );
-		$this->assertTrue( ( new AvailableCurrencies( $this->client ) )->is_available( 'eur' ) );
+	public static function provide_data_for_is_available(): array {
+		return array(
+			array( 'bch', false ),
+			array( 'ada', true ),
+			array( 'btc', true ),
+			array( 'eur', true ),
+		);
 	}
-
 	/**
-	 * Test Setup
+	 * The is_available method looks a currency in the cached result-set up
 	 *
-	 * @return void
+	 * @dataProvider provide_data_for_is_available
 	 */
-	public function setUp(): void {
-		parent::setUp();
-
-		$response = \Mockery::mock( Response::class );
-		$response->shouldReceive( 'get' )->andReturn( self::EXPECTED );
+	public function test_is_available( string $currency, bool $expected ): void {
+		Functions\expect( 'wp_cache_get' )->atLeast()->once()->andReturn( self::EXPECTED );
 
-		$this->client = \Mockery::mock( Client::class );
-		$this->client->shouldReceive( 'get' )->andReturn( $response );
+		$this->assertEquals( $expected, ( new AvailableCurrencies( $this->client ) )->is_available( $currency ) );
 	}
 
 	/**
diff --git a/tests/TestAdminWidget.php b/tests/TestAdminWidget.php
index ac61f8f..43a3441 100644
--- a/tests/TestAdminWidget.php
+++ b/tests/TestAdminWidget.php
@@ -4,6 +4,7 @@
 
 use lloc\Nowpayments\AdminWidget;
 use lloc\Nowpayments\Integration\ApiStatus;
+use lloc\Nowpayments\Integration\ApiStatusInterface;
 use lloc\Nowpayments\Rest\Client;
 use lloc\Nowpayments\Rest\Service;
 use Brain\Monkey\Functions;
@@ -11,13 +12,14 @@
 class TestAdminWidget extends LlocTestCase {
 
 	public function test_render() {
+
 		$service = \Mockery::mock( Service::class );
 		$service->shouldReceive( 'info' )->once()->andReturn( 'abc' );
 
 		$client = \Mockery::mock( Client::class );
 		$client->shouldReceive( 'get_service' )->once()->andReturn( $service );
 
-		$status = \Mockery::mock( ApiStatus::class );
+		$status = \Mockery::mock( ApiStatusInterface::class );
 		$status->shouldReceive( 'get' )->once()->andReturn( array( 'message' => 'def' ) );
 		$status->shouldReceive( 'get_client' )->once()->andReturn( $client );