diff --git a/package.json b/package.json
index fbe67af..4612c1b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "fake-toss-payments-server",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "Fake toss-payments server for testing",
   "main": "lib/index.js",
   "typings": "lib/index.d.ts",
diff --git a/packages/api/package.json b/packages/api/package.json
index a05712b..406b25d 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -1,6 +1,6 @@
 {
   "name": "toss-payments-server-api",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "Toss Payments Server API",
   "main": "lib/index.js",
   "typings": "lib/index.d.ts",
@@ -15,7 +15,7 @@
   },
   "homepage": "https://github.com/samchon/fake-toss-payments-server",
   "dependencies": {
-    "@nestia/fetcher": "^2.0.3",
+    "@nestia/fetcher": "^2.0.4",
     "typia": "^5.0.4"
   },
   "keywords": [
diff --git a/packages/api/swagger.json b/packages/api/swagger.json
index c50716e..c1f4cd3 100644
--- a/packages/api/swagger.json
+++ b/packages/api/swagger.json
@@ -13,7 +13,7 @@
   "info": {
     "title": "Toss Payments API",
     "description": "Built by [fake-toss-payments-server](https://github.com/samchon/fake-toss-payments-server) with [nestia](https://github.com/samchon/nestia)",
-    "version": "2.0.3",
+    "version": "2.0.4",
     "license": {
       "name": "MIT"
     }
diff --git a/src/api/functional/internal/index.ts b/src/api/functional/internal/index.ts
index 7e4ca64..069c56b 100644
--- a/src/api/functional/internal/index.ts
+++ b/src/api/functional/internal/index.ts
@@ -27,7 +27,7 @@ import { NestiaSimulator } from "../../utils/NestiaSimulator";
  * @param input 웹훅 이벤트 정보
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossInternalController.webhook
+ * @controller [object Object]
  * @path POST /internal/webhook
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
@@ -105,7 +105,7 @@ export namespace webhook {
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossInternalController.deposit
+ * @controller [object Object]
  * @path GET /internal/:paymentKey/deposit
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/billing/authorizations/card/index.ts b/src/api/functional/v1/billing/authorizations/card/index.ts
index 97c4123..7ad9356 100644
--- a/src/api/functional/v1/billing/authorizations/card/index.ts
+++ b/src/api/functional/v1/billing/authorizations/card/index.ts
@@ -28,7 +28,7 @@ import { NestiaSimulator } from "../../../../../utils/NestiaSimulator";
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossBillingController.store
+ * @controller [object Object]
  * @path POST /v1/billing/authorizations/card
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/billing/authorizations/index.ts b/src/api/functional/v1/billing/authorizations/index.ts
index 9515f50..b70b4d2 100644
--- a/src/api/functional/v1/billing/authorizations/index.ts
+++ b/src/api/functional/v1/billing/authorizations/index.ts
@@ -29,7 +29,7 @@ export * as card from "./card";
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossBillingController.at
+ * @controller [object Object]
  * @path POST /v1/billing/authorizations/:billingKey
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/billing/index.ts b/src/api/functional/v1/billing/index.ts
index d362dfc..f0c22d1 100644
--- a/src/api/functional/v1/billing/index.ts
+++ b/src/api/functional/v1/billing/index.ts
@@ -37,7 +37,7 @@ export * as authorizations from "./authorizations";
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossBillingController.pay
+ * @controller [object Object]
  * @path POST /v1/billing/:billingKey
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/cash_receipts/index.ts b/src/api/functional/v1/cash_receipts/index.ts
index 9cc2553..fbda66f 100644
--- a/src/api/functional/v1/cash_receipts/index.ts
+++ b/src/api/functional/v1/cash_receipts/index.ts
@@ -19,7 +19,7 @@ import { NestiaSimulator } from "../../../utils/NestiaSimulator";
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossCashReceiptsController.store
+ * @controller [object Object]
  * @path POST /v1/cash-receipts
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
@@ -99,7 +99,7 @@ export namespace store {
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossCashReceiptsController.cancel
+ * @controller [object Object]
  * @path POST /v1/cash-receipts/:receiptKey/cancel
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/payments/index.ts b/src/api/functional/v1/payments/index.ts
index e45c3fe..368e1d7 100644
--- a/src/api/functional/v1/payments/index.ts
+++ b/src/api/functional/v1/payments/index.ts
@@ -31,7 +31,7 @@ import { NestiaSimulator } from "../../../utils/NestiaSimulator";
  * @returns 결제 정보
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossPaymentsController.at
+ * @controller [object Object]
  * @path GET /v1/payments/:paymentKey
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
@@ -117,7 +117,7 @@ export namespace at {
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossPaymentsController.key_in
+ * @controller [object Object]
  * @path POST /v1/payments/key-in
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
@@ -207,7 +207,7 @@ export namespace key_in {
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossPaymentsController.approve
+ * @controller [object Object]
  * @path POST /v1/payments/:paymentKey
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
@@ -296,7 +296,7 @@ export namespace approve {
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossPaymentsController.cancel
+ * @controller [object Object]
  * @path POST /v1/payments/:paymentKey/cancel
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/api/functional/v1/virtual_accounts/index.ts b/src/api/functional/v1/virtual_accounts/index.ts
index 3c58e4e..4d717c1 100644
--- a/src/api/functional/v1/virtual_accounts/index.ts
+++ b/src/api/functional/v1/virtual_accounts/index.ts
@@ -35,7 +35,7 @@ import { NestiaSimulator } from "../../../utils/NestiaSimulator";
  * @security basic
  * @author Jeongho Nam - https://github.com/samchon
  * 
- * @controller FakeTossVirtualAccountsController.store
+ * @controller [object Object]
  * @path POST /v1/virtual-accounts
  * @nestia Generated by Nestia - https://github.com/samchon/nestia
  */
diff --git a/src/controllers/FakeTossPaymentsController.ts b/src/controllers/FakeTossPaymentsController.ts
index bb832da..e6450de 100644
--- a/src/controllers/FakeTossPaymentsController.ts
+++ b/src/controllers/FakeTossPaymentsController.ts
@@ -166,23 +166,34 @@ export class FakeTossPaymentsController {
         FakeTossUserAuth.authorize(request);
 
         const payment: ITossPayment = FakeTossStorage.payments.get(paymentKey);
+        const amount: number = input.cancelAmount ?? payment.totalAmount;
+
+        if (payment.balanceAmount < amount)
+            throw new nest.UnprocessableEntityException(
+                "Balance amount is not enough.",
+            );
+
         payment.status = "CANCELED";
         payment.cancels ??= [];
         payment.cancels.push({
-            cancelAmount: input.cancelAmount || payment.totalAmount,
+            cancelAmount: amount,
             cancelReason: input.cancelReason,
-            taxFreeAmount: input.taxFreeAmount || 0,
-            taxAmount: input.taxAmount || 0,
-            refundableAmount: input.refundableAmount || payment.totalAmount,
+            taxFreeAmount: input.taxFreeAmount ?? 0,
+            taxAmount: input.taxAmount ?? 0,
+            refundableAmount: input.refundableAmount ?? payment.totalAmount,
             canceledAt: new Date().toISOString(),
         });
+        payment.balanceAmount -= amount;
 
         FakeTossWebhookProvider.webhook({
             eventType: "PAYMENT_STATUS_CHANGED",
             data: {
                 paymentKey: payment.paymentKey,
                 orderId: payment.orderId,
-                status: "CANCELED",
+                status:
+                    payment.balanceAmount === 0
+                        ? "CANCELED"
+                        : "PARTIAL_CANCELED",
             },
         }).catch(() => {});
 
diff --git a/test/features/internal/validate_fake_payment_cancel.ts b/test/features/internal/validate_fake_payment_cancel.ts
new file mode 100644
index 0000000..1a5a203
--- /dev/null
+++ b/test/features/internal/validate_fake_payment_cancel.ts
@@ -0,0 +1,77 @@
+import { TestValidator } from "@nestia/e2e";
+import { sleep_for } from "tstl";
+import typia from "typia";
+
+import toss from "toss-payments-server-api";
+import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
+import { ITossPaymentWebhook } from "toss-payments-server-api/lib/structures/ITossPaymentWebhook";
+
+import { FakeTossStorage } from "../../../src/providers/FakeTossStorage";
+import { TestConnection } from "../../internal/TestConnection";
+
+export const validate_fake_payment_cancel =
+    (generator: () => Promise<ITossPayment>, virtual: boolean) => async () => {
+        // 결제 완료
+        const init: ITossPayment = await generator();
+
+        // 검증 로직 준비
+        const validate = (cancelled: boolean) => (p: ITossPayment) => {
+            TestValidator.equals("balanceAmount")(
+                cancelled ? 0 : p.totalAmount,
+            )(p.balanceAmount);
+            TestValidator.equals("cancelAmount")(
+                (p.cancels ?? [])
+                    .map((c) => c.cancelAmount)
+                    .reduce((a, b) => a + b, 0),
+            )(cancelled ? p.totalAmount : 0);
+            TestValidator.equals("cancels?.length")(cancelled ? 1 : 0)(
+                p.cancels?.length ?? 0,
+            );
+            TestValidator.predicate("cancel_history")(
+                cancelled
+                    ? () =>
+                          p.cancels?.length === 1 &&
+                          p.cancels?.[0].cancelAmount === p.totalAmount
+                    : () => !p.cancels?.length,
+            );
+        };
+
+        // 결제 취소 전 검증
+        validate(false)(init);
+
+        // 결제 취소하기 (전액)
+        const cancelled: ITossPayment =
+            await toss.functional.v1.payments.cancel(
+                TestConnection.FAKE,
+                init.paymentKey,
+                {
+                    paymentKey: init.paymentKey,
+                    cancelReason: "테스트 결제 취소",
+                    cancelAmount: init.totalAmount,
+                    refundReceiveAccount: virtual
+                        ? {
+                              bank: "국민은행",
+                              accountNumber: "12345678901234",
+                              holderName: "홍길동",
+                          }
+                        : undefined,
+                },
+            );
+        typia.assert(cancelled);
+        validate(true)(cancelled);
+
+        // 웹훅 검증
+        await sleep_for(50);
+        const webhook: ITossPaymentWebhook = FakeTossStorage.webhooks.get(
+            init.paymentKey,
+        );
+        TestValidator.equals("status")(webhook.data.status)("CANCELED");
+
+        // 결제 내역 재 조회하여 검증
+        const reloaded: ITossPayment = await toss.functional.v1.payments.at(
+            TestConnection.FAKE,
+            init.paymentKey,
+        );
+        typia.assert(reloaded);
+        validate(true)(reloaded);
+    };
diff --git a/test/features/internal/validate_fake_payment_cancel_over.ts b/test/features/internal/validate_fake_payment_cancel_over.ts
new file mode 100644
index 0000000..ebfa5ef
--- /dev/null
+++ b/test/features/internal/validate_fake_payment_cancel_over.ts
@@ -0,0 +1,44 @@
+import { TestValidator } from "@nestia/e2e";
+import typia from "typia";
+
+import toss from "toss-payments-server-api";
+import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
+
+import { TestConnection } from "../../internal/TestConnection";
+
+export const validate_fake_payment_cancel_over =
+    (generator: () => Promise<ITossPayment>, virtual: boolean) => async () => {
+        // 결제 완료
+        const payment: ITossPayment = await generator();
+
+        // 결제 취소하기 (전액 + 100)
+        await TestValidator.error("over")(() =>
+            toss.functional.v1.payments.cancel(
+                TestConnection.FAKE,
+                payment.paymentKey,
+                {
+                    paymentKey: payment.paymentKey,
+                    cancelReason: "테스트 결제 취소",
+                    cancelAmount: payment.totalAmount + 100,
+                    refundReceiveAccount: virtual
+                        ? {
+                              bank: "국민은행",
+                              accountNumber: "12345678901234",
+                              holderName: "홍길동",
+                          }
+                        : undefined,
+                },
+            ),
+        );
+
+        // 결제 내역 재 조회하여 다시 검증
+        const reloaded: ITossPayment = await toss.functional.v1.payments.at(
+            TestConnection.FAKE,
+            payment.paymentKey,
+        );
+        typia.assert(reloaded);
+        TestValidator.equals("balance")(payment.balanceAmount)(
+            payment.totalAmount,
+        );
+        TestValidator.equals("cancels.length")(payment.cancels?.length ?? 0)(0);
+    };
diff --git a/test/features/internal/validate_fake_payment_cancel_partial.ts b/test/features/internal/validate_fake_payment_cancel_partial.ts
new file mode 100644
index 0000000..d3cef5d
--- /dev/null
+++ b/test/features/internal/validate_fake_payment_cancel_partial.ts
@@ -0,0 +1,69 @@
+import { ArrayUtil, TestValidator } from "@nestia/e2e";
+import { sleep_for } from "tstl";
+import typia from "typia";
+
+import toss from "toss-payments-server-api";
+import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
+
+import { FakeTossStorage } from "../../../src/providers/FakeTossStorage";
+import { TestConnection } from "../../internal/TestConnection";
+
+export const validate_fake_payment_cancel_partial =
+    (generator: () => Promise<ITossPayment>, virtual: boolean) => async () => {
+        // 결제 완료
+        const init: ITossPayment = await generator();
+
+        // 검증 로직 준비
+        const validate = (count: number) => (p: ITossPayment) => {
+            const expected: number = (p.totalAmount / 5) * count;
+
+            // VALIDATE CANCELLED AMOUNT
+            TestValidator.equals("balanceAmount")(p.totalAmount - expected)(
+                p.balanceAmount,
+            );
+            TestValidator.equals("cancelAmount")(
+                (p.cancels ?? [])
+                    .map((c) => c.cancelAmount)
+                    .reduce((a, b) => a + b, 0),
+            )(expected);
+            TestValidator.equals("cancels?.length")(count)(
+                p.cancels?.length ?? 0,
+            );
+
+            // VALIDATE WEBHOOOK
+            if (count !== 0) {
+                const webhook = FakeTossStorage.webhooks.get(p.paymentKey);
+                TestValidator.equals("status")(webhook.data.status)(
+                    count !== 5 ? "PARTIAL_CANCELED" : "CANCELED",
+                );
+            }
+        };
+
+        // 결제 취소 전 검증
+        await sleep_for(100);
+        validate(0)(init);
+
+        // 5 회에 걸쳐 분할 취소 하기
+        await ArrayUtil.asyncRepeat(5)(async (i) => {
+            const cancelled: ITossPayment =
+                await toss.functional.v1.payments.cancel(
+                    TestConnection.FAKE,
+                    init.paymentKey,
+                    {
+                        paymentKey: init.paymentKey,
+                        cancelReason: "테스트 결제 취소",
+                        cancelAmount: init.totalAmount / 5,
+                        refundReceiveAccount: virtual
+                            ? {
+                                  bank: "국민은행",
+                                  accountNumber: "12345678901234",
+                                  holderName: "홍길동",
+                              }
+                            : undefined,
+                    },
+                );
+            typia.assert(cancelled);
+            await sleep_for(100);
+            validate(i + 1)(cancelled);
+        });
+    };
diff --git a/test/features/examples/test_fake_billing_payment.ts b/test/features/test_fake_billing_payment.ts
similarity index 74%
rename from test/features/examples/test_fake_billing_payment.ts
rename to test/features/test_fake_billing_payment.ts
index 2302ca3..40125b2 100644
--- a/test/features/examples/test_fake_billing_payment.ts
+++ b/test/features/test_fake_billing_payment.ts
@@ -1,4 +1,5 @@
-import { assert } from "typia";
+import { TestValidator } from "@nestia/e2e";
+import typia from "typia";
 import { v4 } from "uuid";
 
 import toss from "toss-payments-server-api";
@@ -6,9 +7,9 @@ import { ITossBilling } from "toss-payments-server-api/lib/structures/ITossBilli
 import { ITossCardPayment } from "toss-payments-server-api/lib/structures/ITossCardPayment";
 import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
 
-import { TestConnection } from "../../internal/TestConnection";
+import { TestConnection } from "../internal/TestConnection";
 
-export async function test_fake_billing_payment(): Promise<void> {
+export async function test_fake_billing_payment(): Promise<ITossPayment> {
     // 간편 결제 카드 등록하기
     const billing: ITossBilling =
         await toss.functional.v1.billing.authorizations.card.store(
@@ -23,7 +24,7 @@ export async function test_fake_billing_payment(): Promise<void> {
                 consumerName: "남정호",
             },
         );
-    assert<ITossBilling>(billing);
+    typia.assert<ITossBilling>(billing);
 
     // 간편 결제 카드로 결제하기
     const payment: ITossPayment = await toss.functional.v1.billing.pay(
@@ -37,11 +38,10 @@ export async function test_fake_billing_payment(): Promise<void> {
             amount: 10_000,
         },
     );
-    assert<ITossCardPayment>(payment);
+    typia.assert<ITossCardPayment>(payment);
 
     // 간편 결제 카드로 결제시, 별도 승인 처리가 필요 없음
-    if (payment.approvedAt === null || payment.status !== "DONE")
-        throw new Error(
-            "Bug on TossBillingController.pay(): failed to billing pay.",
-        );
+    TestValidator.equals("approvedAt")(!!payment.approvedAt)(true);
+    TestValidator.equals("status")(payment.status)("DONE");
+    return payment;
 }
diff --git a/test/features/test_fake_billing_payment_cancel.ts b/test/features/test_fake_billing_payment_cancel.ts
new file mode 100644
index 0000000..01e2aa3
--- /dev/null
+++ b/test/features/test_fake_billing_payment_cancel.ts
@@ -0,0 +1,7 @@
+import { validate_fake_payment_cancel } from "./internal/validate_fake_payment_cancel";
+import { test_fake_billing_payment } from "./test_fake_billing_payment";
+
+export const test_fake_billing_payment_cancel = validate_fake_payment_cancel(
+    () => test_fake_billing_payment(),
+    false,
+);
diff --git a/test/features/test_fake_billing_payment_cancel_over.ts b/test/features/test_fake_billing_payment_cancel_over.ts
new file mode 100644
index 0000000..efb6e9c
--- /dev/null
+++ b/test/features/test_fake_billing_payment_cancel_over.ts
@@ -0,0 +1,5 @@
+import { validate_fake_payment_cancel_over } from "./internal/validate_fake_payment_cancel_over";
+import { test_fake_billing_payment } from "./test_fake_billing_payment";
+
+export const test_fake_billing_payment_cancel_over =
+    validate_fake_payment_cancel_over(() => test_fake_billing_payment(), false);
diff --git a/test/features/test_fake_billing_payment_cancel_partial.ts b/test/features/test_fake_billing_payment_cancel_partial.ts
new file mode 100644
index 0000000..2741308
--- /dev/null
+++ b/test/features/test_fake_billing_payment_cancel_partial.ts
@@ -0,0 +1,8 @@
+import { validate_fake_payment_cancel_partial } from "./internal/validate_fake_payment_cancel_partial";
+import { test_fake_billing_payment } from "./test_fake_billing_payment";
+
+export const test_fake_billing_payment_cancel_partial =
+    validate_fake_payment_cancel_partial(
+        () => test_fake_billing_payment(),
+        false,
+    );
diff --git a/test/features/examples/test_fake_card_payment.ts b/test/features/test_fake_card_payment.ts
similarity index 87%
rename from test/features/examples/test_fake_card_payment.ts
rename to test/features/test_fake_card_payment.ts
index a5f8627..f543c2f 100644
--- a/test/features/examples/test_fake_card_payment.ts
+++ b/test/features/test_fake_card_payment.ts
@@ -1,13 +1,14 @@
 import { TestValidator } from "@nestia/e2e";
+import typia from "typia";
 import { v4 } from "uuid";
 
 import toss from "toss-payments-server-api";
 import { ITossCardPayment } from "toss-payments-server-api/lib/structures/ITossCardPayment";
 import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
 
-import { TestConnection } from "../../internal/TestConnection";
+import { TestConnection } from "../internal/TestConnection";
 
-export async function test_fake_card_payment(): Promise<void> {
+export async function test_fake_card_payment(): Promise<ITossCardPayment> {
     //----
     // 결제하기
     //----
@@ -39,6 +40,7 @@ export async function test_fake_card_payment(): Promise<void> {
             __approved: false,
         },
     );
+    typia.assert(payment);
 
     // 잘못된 `orderId` 로 승인 처리시, 불발됨
     await TestValidator.error(
@@ -77,8 +79,9 @@ export async function test_fake_card_payment(): Promise<void> {
             amount: payment.totalAmount,
         },
     );
-    if (approved.approvedAt === null || approved.status !== "DONE")
-        throw new Error(
-            "Bug on FakeTossPaymentsController.approve(): failed to approve.",
-        );
+    const card: ITossCardPayment = typia.assert<ITossCardPayment>(approved);
+    TestValidator.equals("approvedAt")(!!card.approvedAt)(true);
+    TestValidator.equals("status")(card.status)("DONE");
+
+    return card;
 }
diff --git a/test/features/test_fake_card_payment_cancel.ts b/test/features/test_fake_card_payment_cancel.ts
new file mode 100644
index 0000000..784d5d7
--- /dev/null
+++ b/test/features/test_fake_card_payment_cancel.ts
@@ -0,0 +1,7 @@
+import { validate_fake_payment_cancel } from "./internal/validate_fake_payment_cancel";
+import { test_fake_card_payment } from "./test_fake_card_payment";
+
+export const test_fake_card_payment_cancel = validate_fake_payment_cancel(
+    () => test_fake_card_payment(),
+    false,
+);
diff --git a/test/features/test_fake_card_payment_cancel_over.ts b/test/features/test_fake_card_payment_cancel_over.ts
new file mode 100644
index 0000000..f8427aa
--- /dev/null
+++ b/test/features/test_fake_card_payment_cancel_over.ts
@@ -0,0 +1,5 @@
+import { validate_fake_payment_cancel_over } from "./internal/validate_fake_payment_cancel_over";
+import { test_fake_card_payment } from "./test_fake_card_payment";
+
+export const test_fake_card_payment_cancel_over =
+    validate_fake_payment_cancel_over(() => test_fake_card_payment(), false);
diff --git a/test/features/test_fake_card_payment_cancel_partial.ts b/test/features/test_fake_card_payment_cancel_partial.ts
new file mode 100644
index 0000000..4e4a7de
--- /dev/null
+++ b/test/features/test_fake_card_payment_cancel_partial.ts
@@ -0,0 +1,5 @@
+import { validate_fake_payment_cancel_partial } from "./internal/validate_fake_payment_cancel_partial";
+import { test_fake_card_payment } from "./test_fake_card_payment";
+
+export const test_fake_card_payment_cancel_partial =
+    validate_fake_payment_cancel_partial(() => test_fake_card_payment(), false);
diff --git a/test/features/examples/test_fake_cash_receipt.ts b/test/features/test_fake_cash_receipt.ts
similarity index 62%
rename from test/features/examples/test_fake_cash_receipt.ts
rename to test/features/test_fake_cash_receipt.ts
index 691f92b..ef229ff 100644
--- a/test/features/examples/test_fake_cash_receipt.ts
+++ b/test/features/test_fake_cash_receipt.ts
@@ -1,14 +1,17 @@
-import { assert } from "typia";
+import { TestValidator } from "@nestia/e2e";
+import typia from "typia";
 
 import toss from "toss-payments-server-api";
 import { ITossCashReceipt } from "toss-payments-server-api/lib/structures/ITossCashReceipt";
 import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
+import { ITossVirtualAccountPayment } from "toss-payments-server-api/lib/structures/ITossVirtualAccountPayment";
 
-import { TestConnection } from "../../internal/TestConnection";
+import { TestConnection } from "../internal/TestConnection";
 import { test_fake_virtual_account_payment } from "./test_fake_virtual_account_payment";
 
 export async function test_fake_cash_receipt(): Promise<void> {
-    const payment: ITossPayment = await test_fake_virtual_account_payment();
+    const payment: ITossVirtualAccountPayment =
+        await test_fake_virtual_account_payment();
     const receipt: ITossCashReceipt =
         await toss.functional.v1.cash_receipts.store(TestConnection.FAKE, {
             type: "소득공제",
@@ -18,14 +21,14 @@ export async function test_fake_cash_receipt(): Promise<void> {
             registrationNumber: "8803111******",
             amount: payment.totalAmount,
         });
-    assert<ITossCashReceipt>(receipt);
+    typia.assert<ITossCashReceipt>(receipt);
 
     const reloaded: ITossPayment = await toss.functional.v1.payments.at(
         TestConnection.FAKE,
         payment.paymentKey,
     );
-    if (reloaded.cashReceipt === null)
-        throw new Error(
-            "Bug on cash_receipts.store(): failed to store it on the payment.",
-        );
+    typia.assert<ITossPayment>(reloaded);
+    TestValidator.equals("receipt")(reloaded.cashReceipt?.receiptUrl)(
+        receipt.receiptUrl,
+    );
 }
diff --git a/test/features/storage/test_storage_capacity.ts b/test/features/test_fake_storage_capacity.ts
similarity index 88%
rename from test/features/storage/test_storage_capacity.ts
rename to test/features/test_fake_storage_capacity.ts
index bb554d5..31cc328 100644
--- a/test/features/storage/test_storage_capacity.ts
+++ b/test/features/test_fake_storage_capacity.ts
@@ -8,12 +8,12 @@ import toss from "toss-payments-server-api";
 import { ITossBilling } from "toss-payments-server-api/lib/structures/ITossBilling";
 import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
 
-import { TossFakeConfiguration } from "../../../src/FakeTossConfiguration";
-import { FakeTossStorage } from "../../../src/providers/FakeTossStorage";
-import { AdvancedRandomGenerator } from "../../internal/AdvancedRandomGenerator";
-import { TestConnection } from "../../internal/TestConnection";
+import { TossFakeConfiguration } from "../../src/FakeTossConfiguration";
+import { FakeTossStorage } from "../../src/providers/FakeTossStorage";
+import { AdvancedRandomGenerator } from "../internal/AdvancedRandomGenerator";
+import { TestConnection } from "../internal/TestConnection";
 
-export async function test_storage_capacity(): Promise<void> {
+export async function test_fake_storage_capacity(): Promise<void> {
     const capacity: number = TossFakeConfiguration.EXPIRATION.capacity;
 
     FakeTossStorage.payments.clear();
diff --git a/test/features/storage/test_storage_expiration_time.ts b/test/features/test_fake_storage_expiration_time.ts
similarity index 83%
rename from test/features/storage/test_storage_expiration_time.ts
rename to test/features/test_fake_storage_expiration_time.ts
index 2ecff78..db1b51e 100644
--- a/test/features/storage/test_storage_expiration_time.ts
+++ b/test/features/test_fake_storage_expiration_time.ts
@@ -9,12 +9,12 @@ import toss from "toss-payments-server-api";
 import { ITossCardPayment } from "toss-payments-server-api/lib/structures/ITossCardPayment";
 import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayment";
 
-import { TossFakeConfiguration } from "../../../src/FakeTossConfiguration";
-import { FakeTossStorage } from "../../../src/providers/FakeTossStorage";
-import { AdvancedRandomGenerator } from "../../internal/AdvancedRandomGenerator";
-import { TestConnection } from "../../internal/TestConnection";
+import { TossFakeConfiguration } from "../../src/FakeTossConfiguration";
+import { FakeTossStorage } from "../../src/providers/FakeTossStorage";
+import { AdvancedRandomGenerator } from "../internal/AdvancedRandomGenerator";
+import { TestConnection } from "../internal/TestConnection";
 
-export async function test_storage_expiration_time(): Promise<void> {
+export async function test_fake_storage_expiration_time(): Promise<void> {
     const time: number = TossFakeConfiguration.EXPIRATION.time;
     FakeTossStorage.payments.clear();
     TossFakeConfiguration.EXPIRATION.time = 1;
diff --git a/test/features/examples/test_fake_virtual_account_payment.ts b/test/features/test_fake_virtual_account_payment.ts
similarity index 81%
rename from test/features/examples/test_fake_virtual_account_payment.ts
rename to test/features/test_fake_virtual_account_payment.ts
index 626d1a1..b0cfd9d 100644
--- a/test/features/examples/test_fake_virtual_account_payment.ts
+++ b/test/features/test_fake_virtual_account_payment.ts
@@ -1,4 +1,5 @@
-import { assert } from "typia";
+import { TestValidator } from "@nestia/e2e";
+import typia from "typia";
 import { v4 } from "uuid";
 
 import toss from "toss-payments-server-api";
@@ -6,9 +7,9 @@ import { ITossPayment } from "toss-payments-server-api/lib/structures/ITossPayme
 import { ITossPaymentWebhook } from "toss-payments-server-api/lib/structures/ITossPaymentWebhook";
 import { ITossVirtualAccountPayment } from "toss-payments-server-api/lib/structures/ITossVirtualAccountPayment";
 
-import { FakeTossStorage } from "../../../src/providers/FakeTossStorage";
-import { AdvancedRandomGenerator } from "../../internal/AdvancedRandomGenerator";
-import { TestConnection } from "../../internal/TestConnection";
+import { FakeTossStorage } from "../../src/providers/FakeTossStorage";
+import { AdvancedRandomGenerator } from "../internal/AdvancedRandomGenerator";
+import { TestConnection } from "../internal/TestConnection";
 
 export async function test_fake_virtual_account_payment(): Promise<ITossVirtualAccountPayment> {
     //----
@@ -41,7 +42,7 @@ export async function test_fake_virtual_account_payment(): Promise<ITossVirtualA
             // 고의 미승인 처리
             __approved: false,
         });
-    assert<ITossVirtualAccountPayment>(payment);
+    typia.assert(payment);
 
     // 결제 요청 승인하기
     //
@@ -54,7 +55,7 @@ export async function test_fake_virtual_account_payment(): Promise<ITossVirtualA
             amount: payment.totalAmount,
         },
     );
-    assert<ITossVirtualAccountPayment>(approved);
+    typia.assert<ITossVirtualAccountPayment>(approved);
 
     //----
     // 입금하기
@@ -71,13 +72,10 @@ export async function test_fake_virtual_account_payment(): Promise<ITossVirtualA
         TestConnection.FAKE,
         payment.paymentKey,
     );
-    assert<ITossVirtualAccountPayment>(reloaded);
+    typia.assert<ITossVirtualAccountPayment>(reloaded);
 
     // 결제 완료 처리되었음을 알 수 있다
-    if (reloaded.status !== "DONE")
-        throw new Error(
-            "Bug on FakeTossWebhookProvider.webhook(): failed to generate the exact webhook event.",
-        );
+    TestValidator.equals("status")(reloaded.status)("DONE");
 
     // 실제로 웹훅 이벤트 발생 내역을 보면,
     // 고객이 가상 계좌에 결제 금액을 입금하였을 때,
@@ -85,10 +83,7 @@ export async function test_fake_virtual_account_payment(): Promise<ITossVirtualA
     const webhook: ITossPaymentWebhook = FakeTossStorage.webhooks.get(
         payment.paymentKey,
     );
-    if (webhook.data.status !== "DONE")
-        throw new Error(
-            "Bug on FakeTossInternalController.webhook(): failed to listen the webhook event.",
-        );
+    TestValidator.equals("status")(webhook.data.status)("DONE");
 
     // if condition 에 의하여 자동 다운 캐스팅 됨.
     payment.virtualAccount.accountNumber;
diff --git a/test/features/test_fake_virtual_account_payment_cancel.ts b/test/features/test_fake_virtual_account_payment_cancel.ts
new file mode 100644
index 0000000..e34cc68
--- /dev/null
+++ b/test/features/test_fake_virtual_account_payment_cancel.ts
@@ -0,0 +1,8 @@
+import { validate_fake_payment_cancel } from "./internal/validate_fake_payment_cancel";
+import { test_fake_virtual_account_payment } from "./test_fake_virtual_account_payment";
+
+export const test_fake_virtual_account_payment_cancel =
+    validate_fake_payment_cancel(
+        () => test_fake_virtual_account_payment(),
+        true,
+    );
diff --git a/test/features/test_fake_virtual_account_payment_cancel_over.ts b/test/features/test_fake_virtual_account_payment_cancel_over.ts
new file mode 100644
index 0000000..ed42c82
--- /dev/null
+++ b/test/features/test_fake_virtual_account_payment_cancel_over.ts
@@ -0,0 +1,8 @@
+import { validate_fake_payment_cancel_over } from "./internal/validate_fake_payment_cancel_over";
+import { test_fake_virtual_account_payment } from "./test_fake_virtual_account_payment";
+
+export const test_fake_virtual_account_payment_cancel_over =
+    validate_fake_payment_cancel_over(
+        () => test_fake_virtual_account_payment(),
+        true,
+    );
diff --git a/test/features/test_fake_virtual_account_payment_cancel_partial.ts b/test/features/test_fake_virtual_account_payment_cancel_partial.ts
new file mode 100644
index 0000000..cc74f56
--- /dev/null
+++ b/test/features/test_fake_virtual_account_payment_cancel_partial.ts
@@ -0,0 +1,8 @@
+import { validate_fake_payment_cancel_partial } from "./internal/validate_fake_payment_cancel_partial";
+import { test_fake_virtual_account_payment } from "./test_fake_virtual_account_payment";
+
+export const test_fake_virtual_account_payment_cancel_partial =
+    validate_fake_payment_cancel_partial(
+        () => test_fake_virtual_account_payment(),
+        true,
+    );