diff --git a/tests/unit/includes/gateway/abstract-omise-payment-offline-test.php b/tests/unit/includes/gateway/abstract-omise-payment-offline-test.php
index be048760..0be53dc6 100644
--- a/tests/unit/includes/gateway/abstract-omise-payment-offline-test.php
+++ b/tests/unit/includes/gateway/abstract-omise-payment-offline-test.php
@@ -1,28 +1,15 @@
 <?php
 
-use PHPUnit\Framework\TestCase;
+require_once __DIR__ . '/bootstrap-test-setup.php';
 
-class Omise_Payment_Offline_Test extends TestCase
+class Omise_Payment_Offline_Test extends Bootstrap_Test_Setup
 {
     public function setUp(): void
     {
+        parent::setUp();
         require_once __DIR__ . '/../../../../includes/gateway/abstract-omise-payment-offline.php';
     }
 
-    public function getOrderMock($expectedAmount, $expectedCurrency)
-    {
-        // Create a mock of the $order object
-        $orderMock = Mockery::mock('WC_Order');
-
-        // Define expectations for the mock
-        $orderMock->shouldReceive('get_currency')
-            ->andReturn($expectedCurrency);
-        $orderMock->shouldReceive('get_total')
-            ->andReturn($expectedAmount);  // in units
-        $orderMock->shouldReceive('add_meta_data');
-        return $orderMock;
-    }
-
     public function charge()
     {
         $orderMock = $this->getOrderMock(99999, 'THB');
@@ -31,6 +18,5 @@ public function charge()
         $result = $mock->charge('order_123', $orderMock);
 
         var_dump(print_r($result, true));
-
     }
 }
diff --git a/tests/unit/includes/gateway/bootstrap-test-setup.php b/tests/unit/includes/gateway/bootstrap-test-setup.php
new file mode 100644
index 00000000..421dc1db
--- /dev/null
+++ b/tests/unit/includes/gateway/bootstrap-test-setup.php
@@ -0,0 +1,98 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+abstract class Bootstrap_Test_Setup extends TestCase
+{
+    public $sourceType;
+
+    public function setUp(): void
+    {
+        // mocking WP built-in functions
+        if (!function_exists('wp_kses')) {
+            function wp_kses() {}
+        }
+
+        if (!function_exists('add_action')) {
+            function add_action() {}
+        }
+
+        if (!function_exists('sanitize_text_field')) {
+            function sanitize_text_field() {
+                return 'Sanitized text';
+            }
+        }
+    }
+
+    public function getOrderMock($expectedAmount, $expectedCurrency)
+    {
+        // Create a mock of the $order object
+        $orderMock = Mockery::mock('WC_Order');
+
+        // Define expectations for the mock
+        $orderMock->shouldReceive('get_currency')
+            ->andReturn($expectedCurrency);
+        $orderMock->shouldReceive('get_total')
+            ->andReturn($expectedAmount);  // in units
+        $orderMock->shouldReceive('add_meta_data');
+        $orderMock->shouldReceive('get_billing_phone')
+            ->andReturn('1234567890');
+        $orderMock->shouldReceive('get_address')
+            ->andReturn([
+                'country' => 'Thailand',
+                'city' => 'Bangkok',
+                'postcode' => '10110',
+                'state' => 'Bangkok',
+                'address_1' => 'Sukumvit Road'
+            ]);
+        $orderMock->shouldReceive('get_items')
+            ->andReturn([
+                [
+                    'name' => 'T Shirt',
+                    'subtotal' => 600,
+                    'qty' => 1,
+                    'product_id' => 'product_123',
+                    'variation_id' => null
+                ]
+            ]);
+        return $orderMock;
+    }
+
+    /**
+     * close mockery after tests are done
+     */
+    public function tearDown(): void
+    {
+        Mockery::close();
+    }
+
+    public function getChargeTest($classObj)
+    {
+        $expectedAmount = 999999;
+        $expectedCurrency = 'thb';
+        $expectedRequest = [
+            "object" => "charge",
+            "id" => "chrg_test_no1t4tnemucod0e51mo",
+            "location" => "/charges/chrg_test_no1t4tnemucod0e51mo",
+            "amount" => $expectedAmount,
+            "currency" => $expectedCurrency
+        ];
+
+        // Create a mock for OmiseCharge
+        $chargeMock = Mockery::mock('overload:OmiseCharge');
+        $chargeMock->shouldReceive('create')->once()->andReturn($expectedRequest);
+
+        $orderMock = $this->getOrderMock($expectedAmount, $expectedCurrency);
+
+        $wcProduct = Mockery::mock('overload:WC_Product');
+        $wcProduct->shouldReceive('get_sku')
+            ->once()
+            ->andReturn('sku_1234');
+
+        $orderId = 'order_123';
+        $result = $classObj->charge($orderId, $orderMock);
+        $this->assertEquals($expectedAmount, $result['amount']);
+        $this->assertEquals($expectedCurrency, $result['currency']);
+    }
+}
+
diff --git a/tests/unit/includes/gateway/class-omise-offsite-test.php b/tests/unit/includes/gateway/class-omise-offsite-test.php
index 8954cc93..79f06b59 100644
--- a/tests/unit/includes/gateway/class-omise-offsite-test.php
+++ b/tests/unit/includes/gateway/class-omise-offsite-test.php
@@ -1,13 +1,15 @@
 <?php
 
-use PHPUnit\Framework\TestCase;
+require_once __DIR__ . '/bootstrap-test-setup.php';
 
-abstract class Omise_Offsite_Test extends TestCase
+abstract class Omise_Offsite_Test extends Bootstrap_Test_Setup
 {
     public $sourceType;
 
     public function setUp(): void
     {
+        parent::setUp();
+
         // Mocking the parent class
         $offsite = Mockery::mock('overload:Omise_Payment_Offsite');
         $offsite->shouldReceive('init_settings');
@@ -18,58 +20,45 @@ public function setUp(): void
                 'source' => [ 'type' => $this->sourceType ]
             ]);
 
-        // mocking WP built-in functions
-        if (!function_exists('wp_kses')) {
-            function wp_kses() {}
-        }
-
-        if (!function_exists('add_action')) {
-            function add_action() {}
-        }
-
         // destroy object and clear memory
         unset($offsite);
     }
 
-    public function getOrderMock($expectedAmount, $expectedCurrency)
-    {
-        // Create a mock of the $order object
-        $orderMock = Mockery::mock('WC_Order');
-
-        // Define expectations for the mock
-        $orderMock->shouldReceive('get_currency')
-            ->andReturn($expectedCurrency);
-        $orderMock->shouldReceive('get_total')
-            ->andReturn($expectedAmount);  // in units
-        $orderMock->shouldReceive('add_meta_data');
-        $orderMock->shouldReceive('get_billing_phone')
-            ->andReturn('1234567890');
-        $orderMock->shouldReceive('get_address')
-            ->andReturn([
-                'country' => 'Thailand',
-                'city' => 'Bangkok',
-                'postcode' => '10110',
-                'state' => 'Bangkok',
-                'address_1' => 'Sukumvit Road'
-            ]);
-        $orderMock->shouldReceive('get_items')
-            ->andReturn([
-                [
-                    'name' => 'T Shirt',
-                    'subtotal' => 600,
-                    'qty' => 1,
-                    'product_id' => 'product_123',
-                    'variation_id' => null
-                ]
-            ]);
-        return $orderMock;
-    }
-
     /**
      * close mockery after tests are done
      */
     public function tearDown(): void
     {
+        parent::tearDown();
         Mockery::close();
     }
+
+    public function getChargeTest($classObj)
+    {
+        $expectedAmount = 999999;
+        $expectedCurrency = 'thb';
+        $expectedRequest = [
+            "object" => "charge",
+            "id" => "chrg_test_no1t4tnemucod0e51mo",
+            "location" => "/charges/chrg_test_no1t4tnemucod0e51mo",
+            "amount" => $expectedAmount,
+            "currency" => $expectedCurrency
+        ];
+
+        // Create a mock for OmiseCharge
+        $chargeMock = Mockery::mock('overload:OmiseCharge');
+        $chargeMock->shouldReceive('create')->once()->andReturn($expectedRequest);
+
+        $orderMock = $this->getOrderMock($expectedAmount, $expectedCurrency);
+
+        $wcProduct = Mockery::mock('overload:WC_Product');
+        $wcProduct->shouldReceive('get_sku')
+            ->once()
+            ->andReturn('sku_1234');
+
+        $orderId = 'order_123';
+        $result = $classObj->charge($orderId, $orderMock);
+        $this->assertEquals($expectedAmount, $result['amount']);
+        $this->assertEquals($expectedCurrency, $result['currency']);
+    }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-alipayplus-hk-test.php b/tests/unit/includes/gateway/class-omise-payment-alipayplus-hk-test.php
index 8c68dd0a..1cccb6e6 100644
--- a/tests/unit/includes/gateway/class-omise-payment-alipayplus-hk-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-alipayplus-hk-test.php
@@ -44,34 +44,8 @@ public function testGetChargeRequest()
 
     public function testCharge()
     {
-        $orderId = 'order_123';
-        $expectedAmount = 999999;
-        $expectedCurrency = 'thb';
-        $expectedRequest = [
-            "object" => "charge",
-            "id" => "chrg_test_no1t4tnemucod0e51mo",
-            "location" => "/charges/chrg_test_no1t4tnemucod0e51mo",
-            "amount" => $expectedAmount,
-            "currency" => $expectedCurrency
-        ];
-
-        // Create a mock for OmiseCharge
-        $chargeMock = Mockery::mock('overload:OmiseCharge');
-        $chargeMock->shouldReceive('create')->once()->andReturn($expectedRequest);
-
-        $orderMock = $this->getOrderMock($expectedAmount, $expectedCurrency);
-
-        $wcProduct = Mockery::mock('overload:WC_Product');
-        $wcProduct->shouldReceive('get_sku')
-            ->once()
-            ->andReturn('sku_1234');
-
         $obj = new Omise_Payment_Alipay_Hk();
-        $result = $obj->charge($orderId, $orderMock);
-
-        $this->assertEquals($expectedAmount, $result['amount']);
-        $this->assertEquals($expectedCurrency, $result['currency']);
-
+        $this->getChargeTest($obj);
         unset($obj);
     }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-atome-test.php b/tests/unit/includes/gateway/class-omise-payment-atome-test.php
index 530cb762..47c1ac9e 100644
--- a/tests/unit/includes/gateway/class-omise-payment-atome-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-atome-test.php
@@ -49,35 +49,10 @@ public function testGetChargeRequest()
 
     public function testCharge()
     {
-        $orderId = 'order_123';
-        $expectedAmount = 999999;
-        $expectedCurrency = 'thb';
-        $expectedRequest = [
-            "object" => "charge",
-            "id" => "chrg_test_no1t4tnemucod0e51mo",
-            "location" => "/charges/chrg_test_no1t4tnemucod0e51mo",
-            "amount" => $expectedAmount,
-            "currency" => $expectedCurrency
-        ];
-
-        // Create a mock for OmiseCharge
-        $chargeMock = Mockery::mock('overload:OmiseCharge');
-        $chargeMock->shouldReceive('create')->once()->andReturn($expectedRequest);
-
-        $orderMock = $this->getOrderMock($expectedAmount, $expectedCurrency);
-
-        $wcProduct = Mockery::mock('overload:WC_Product');
-        $wcProduct->shouldReceive('get_sku')
-            ->once()
-            ->andReturn('sku_1234');
-
         $_POST['omise_atome_phone_default'] = true;
-
         $obj = new Omise_Payment_Atome();
-        $result = $obj->charge($orderId, $orderMock);
-
-        $this->assertEquals($expectedAmount, $result['amount']);
-        $this->assertEquals($expectedCurrency, $result['currency']);
+        $this->getChargeTest($obj);
+        unset($_POST['omise_atome_phone_default']);
         unset($obj);
     }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-installment-test.php b/tests/unit/includes/gateway/class-omise-payment-installment-test.php
index 33a6fd3e..8a16749e 100644
--- a/tests/unit/includes/gateway/class-omise-payment-installment-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-installment-test.php
@@ -88,4 +88,17 @@ public function testGetChargeRequest()
         unset($_POST['source']);
         unset($_POST[$this->sourceType . '_installment_terms']);
     }
+
+    public function testCharge()
+    {
+        $_POST['source'] = ['type' => $this->sourceType];
+        $_POST[$this->sourceType . '_installment_terms'] = 3;
+
+        $obj = new Omise_Payment_Installment();
+        $this->getChargeTest($obj);
+        unset($obj);
+
+        unset($_POST['source']);
+        unset($_POST[$this->sourceType . '_installment_terms']);
+    }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-konbini-test.php b/tests/unit/includes/gateway/class-omise-payment-konbini-test.php
index 23a60044..8ff4b8b0 100644
--- a/tests/unit/includes/gateway/class-omise-payment-konbini-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-konbini-test.php
@@ -1,8 +1,6 @@
 <?php
 
-use PHPUnit\Framework\TestCase;
-
-class Omise_Payment_Konbini_Test extends TestCase
+class Omise_Payment_Konbini_Test extends Omise_Payment_Offline_Test
 {
     public $expectedAmount = 999999;
     public $expectedCurrency = 'thb';
@@ -30,19 +28,6 @@ function sanitize_text_field() {
         }
     }
 
-    public function getOrderMock($expectedAmount, $expectedCurrency)
-    {
-        // Create a mock of the $order object
-        $orderMock = Mockery::mock('WC_Order');
-
-        // Define expectations for the mock
-        $orderMock->shouldReceive('get_currency')
-            ->andReturn($expectedCurrency);
-        $orderMock->shouldReceive('get_total')
-            ->andReturn($expectedAmount);  // in units
-        return $orderMock;
-    }
-
     public function testGetChargeRequest()
     {
         $obj = new Omise_Payment_Konbini();
@@ -71,4 +56,20 @@ public function testGetChargeRequest()
         unset($_POST['omise_konbini_phone']);
         unset($obj);
     }
+
+    public function testCharge()
+    {
+        $_POST['omise_konbini_name'] = 'Sanitized text';
+        $_POST['omise_konbini_email'] = 'omsie@opn.ooo';
+        $_POST['omise_konbini_phone'] = '1234567890';
+
+        $obj = new Omise_Payment_Konbini();
+        $this->getChargeTest($obj);
+        unset($obj);
+
+        unset($_POST['omise_konbini_name']);
+        unset($_POST['omise_konbini_email']);
+        unset($_POST['omise_konbini_phone']);
+        unset($obj);
+    }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-ocbc-digital-test.php b/tests/unit/includes/gateway/class-omise-payment-ocbc-digital-test.php
index 62059b47..d4eeec07 100644
--- a/tests/unit/includes/gateway/class-omise-payment-ocbc-digital-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-ocbc-digital-test.php
@@ -88,33 +88,6 @@ public function getIconReturnsCorrectImageLink()
      */
     public function testCharge()
     {
-        $expectedCurrency = 'SGD';
-        $expectedAmount = 1000000; // in subunits
-        $expectedAmount = 1000000; // in subunits
-        $expectedRequest = [
-            "object" => "charge",
-            "id" => "chrg_test_no1t4tnemucod0e51mo",
-            "location" => "/charges/chrg_test_no1t4tnemucod0e51mo",
-            "amount" => $expectedAmount,
-            "currency" => $expectedCurrency
-        ];
-
-        // Create a mock for OmiseCharge
-        $chargeMock = Mockery::mock('overload:OmiseCharge');
-        $chargeMock->shouldReceive('create')->once()->andReturn($expectedRequest);
-
-        // Create a mock of the $order object
-        $orderMock = Mockery::mock('WC_Order');
-
-        // Define expectations for the mock
-        $orderMock->shouldReceive('get_currency')
-            ->andReturn($expectedCurrency);
-        $orderMock->shouldReceive('get_total')
-            ->andReturn($expectedAmount/100);  // in units
-
-        $order_id = "123";
-        $result = $this->obj->charge($order_id, $orderMock);
-        $this->assertEquals($expectedAmount, $result['amount']);
-        $this->assertEquals($expectedCurrency, $result['currency']);
+        $this->getChargeTest($this->obj);
     }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-touch-n-go-test.php b/tests/unit/includes/gateway/class-omise-payment-touch-n-go-test.php
index 1a18c01e..b565b2e7 100644
--- a/tests/unit/includes/gateway/class-omise-payment-touch-n-go-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-touch-n-go-test.php
@@ -23,4 +23,11 @@ public function restrictedCountriesHasRequiredCountries()
 
         unset($obj);
     }
+
+    // public function testCharge()
+    // {
+    //     $obj = new Omise_Payment_TouchNGo();
+    //     echo '<pre>' . print_r(get_class_methods($obj), true) . '</pre>';
+    //     $this->getChargeTest($obj);
+    // }
 }
diff --git a/tests/unit/includes/gateway/class-omise-payment-truemoney-test.php b/tests/unit/includes/gateway/class-omise-payment-truemoney-test.php
index b9c94652..f71bc0d7 100644
--- a/tests/unit/includes/gateway/class-omise-payment-truemoney-test.php
+++ b/tests/unit/includes/gateway/class-omise-payment-truemoney-test.php
@@ -28,4 +28,12 @@ public function testGetChargeRequest()
         unset($_POST['omise_phone_number_default']);
         unset($obj);
     }
+
+    public function testCharge()
+    {
+        $_POST['omise_phone_number_default'] = true;
+        $obj = new Omise_Payment_Truemoney();
+        // echo '<pre>' . print_r(get_class_methods($obj), true) . '</pre>';
+        $this->getChargeTest($obj);
+    }
 }