diff --git a/client_option_test.go b/client_option_test.go
index b4b9648..1b6d788 100644
--- a/client_option_test.go
+++ b/client_option_test.go
@@ -39,7 +39,7 @@ func TestWithHTTPClient(t *testing.T) {
 	})
 }
 
-func TestWithApiURL(t *testing.T) {
+func TestWithAPIURL(t *testing.T) {
 	t.Run("apiURL is set successfully", func(t *testing.T) {
 		// Setup
 		t.Parallel()
@@ -49,7 +49,7 @@ func TestWithApiURL(t *testing.T) {
 		config := defaultClientConfig()
 
 		// Act
-		WithApiURL(apiURL).apply(config)
+		WithAPIURL(apiURL).apply(config)
 
 		// Assert
 		assert.Equal(t, apiURL, config.apiURL)
@@ -64,7 +64,7 @@ func TestWithApiURL(t *testing.T) {
 		config := defaultClientConfig()
 
 		// Act
-		WithApiURL(apiURL).apply(config)
+		WithAPIURL(apiURL).apply(config)
 
 		// Assert
 		assert.Equal(t, "https://example.com", config.apiURL)
diff --git a/refund_service_test.go b/refund_service_test.go
index 24922e8..caabf89 100644
--- a/refund_service_test.go
+++ b/refund_service_test.go
@@ -28,7 +28,7 @@ func TestRefundService_Refund(t *testing.T) {
 	payload := &RefundParams{
 		ChannelUserMsisdn:         "699999999",
 		Pin:                       "0000",
-		Webhook:                   "https://api.nyangapay.com/v1/y-note",
+		Webhook:                   "https://example.com/webhook",
 		Amount:                    "100",
 		FinalCustomerPhone:        "699999999",
 		FinalCustomerName:         "",