diff --git a/tests/php/Functional/OrderFunctions/MollieOrderTest.php b/tests/php/Functional/OrderFunctions/MollieOrderTest.php
new file mode 100644
index 00000000..6ff51748
--- /dev/null
+++ b/tests/php/Functional/OrderFunctions/MollieOrderTest.php
@@ -0,0 +1,116 @@
+<?php
+
+namespace php\Functional\OrderFunctions;
+
+use Mollie\WooCommerce\Payment\MollieObject;
+use Mollie\WooCommerce\PluginApi\MolliePluginApi;
+use Mollie\WooCommerceTests\TestCase;
+
+use stdClass;
+use function Mollie\WooCommerce\Inc\Api\mollie_capture_order;
+use function Mollie\WooCommerce\Inc\Api\mollie_void_order;
+use function Mollie\WooCommerce\Inc\Api\mollie_refund_order;
+use function Mollie\WooCommerce\Inc\Api\mollie_cancel_order;
+use function Mollie\WooCommerce\Inc\Api\mollie_ship_order;
+
+use \WC_Order;
+
+class MollieApiTest extends TestCase {
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function test_captureOrder_invokes_capturePayment_with_correct_order() {
+        $mockOrder = $this->createMock(WC_Order::class);
+        $mockOrder->method('get_id')->willReturn('123');
+        $capturePaymentMock = $this->getMockBuilder(stdClass::class)
+            ->addMethods(['__invoke'])
+            ->getMock();
+        $capturePaymentClosure = function ($orderId) use ($capturePaymentMock) {
+            $capturePaymentMock->__invoke($orderId);
+        };
+        $capturePaymentMock->expects($this->once())
+            ->method('__invoke')
+            ->with($this->equalTo(123));
+
+        $voidPaymentMock = function() {};
+        $mollieObjectMock = $this->createMock(MollieObject::class);
+
+        MolliePluginApi::init($capturePaymentClosure, $voidPaymentMock, $mollieObjectMock);
+        mollie_capture_order($mockOrder);
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function test_voidOrder_invokes_voidPayment_with_correct_order() {
+        $mockOrder = $this->createMock(WC_Order::class);
+        $mockOrder->method('get_id')->willReturn('123');
+        $voidPaymentMock = $this->getMockBuilder(stdClass::class)
+            ->addMethods(['__invoke'])
+            ->getMock();
+        $voidPaymentClosure = function ($orderId) use ($voidPaymentMock) {
+            $voidPaymentMock->__invoke($orderId);
+        };
+        $voidPaymentMock->expects($this->once())
+            ->method('__invoke')
+            ->with($this->equalTo(123));
+
+        $capturePaymentMock = function() {};
+        $mollieObjectMock = $this->createMock(MollieObject::class);
+
+        MolliePluginApi::init($capturePaymentMock, $voidPaymentClosure, $mollieObjectMock);
+        mollie_void_order($mockOrder);
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function test_refundOrder_with_correct_order() {
+        $mockOrder = $this->createMock(WC_Order::class);
+        $mockOrder->method('get_id')->willReturn('123');
+        $voidPaymentMock = function() {};
+        $capturePaymentMock = function() {};
+        $mollieObjectMock = $this->createConfiguredMock(MollieObject::class, [
+            'processRefund' => true
+        ]);
+        $mollieObjectMock->expects($this->once())->method('processRefund')->with('123', 10.0, 'reason');
+
+        MolliePluginApi::init($capturePaymentMock, $voidPaymentMock, $mollieObjectMock);
+        mollie_refund_order($mockOrder, 10.0, 'reason');
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function test_cancelOrder_with_correct_order() {
+        $mockOrder = $this->createMock(WC_Order::class);
+        $mockOrder->method('get_id')->willReturn('123');
+        $voidPaymentMock = function() {};
+        $capturePaymentMock = function() {};
+        $mollieObjectMock = $this->createConfiguredMock(MollieObject::class, [
+            'cancelOrderAtMollie' => true
+        ]);
+        $mollieObjectMock->expects($this->once())->method('cancelOrderAtMollie')->with('123');
+
+        MolliePluginApi::init($capturePaymentMock, $voidPaymentMock, $mollieObjectMock);
+        mollie_cancel_order($mockOrder);
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function test_shipOrder_with_correct_order() {
+        $mockOrder = $this->createMock(WC_Order::class);
+        $mockOrder->method('get_id')->willReturn('123');
+        $voidPaymentMock = function() {};
+        $capturePaymentMock = function() {};
+        $mollieObjectMock = $this->createConfiguredMock(MollieObject::class, [
+            'shipAndCaptureOrderAtMollie' => true
+        ]);
+        $mollieObjectMock->expects($this->once())->method('shipAndCaptureOrderAtMollie')->with('123');
+
+        MolliePluginApi::init($capturePaymentMock, $voidPaymentMock, $mollieObjectMock);
+        mollie_ship_order($mockOrder);
+    }
+}