diff --git a/packages/stripe/src/stripe.test.ts b/packages/stripe/src/stripe.test.ts
index 7e6c5cd523..24af1ebc0b 100644
--- a/packages/stripe/src/stripe.test.ts
+++ b/packages/stripe/src/stripe.test.ts
@@ -1,11 +1,7 @@
-import type { GenericEndpointContext } from "@better-auth/core";
 import { runWithEndpointContext } from "@better-auth/core/context";
 import type { Auth, User } from "better-auth";
-import { betterAuth } from "better-auth";
 import { memoryAdapter } from "better-auth/adapters/memory";
-import { createAuthClient } from "better-auth/client";
-import { setCookieToHeader } from "better-auth/cookies";
-import { bearer } from "better-auth/plugins";
+import { getTestInstance } from "better-auth/test";
 import type Stripe from "stripe";
 import { beforeEach, describe, expect, expectTypeOf, it, vi } from "vitest";
 import type { StripePlugin } from ".";
@@ -50,10 +46,12 @@ describe("stripe type", () => {
 		expectTypeOf<MyAuth["api"]["cancelSubscriptionCallback"]>().toBeFunction();
 		expectTypeOf<MyAuth["api"]["cancelSubscription"]>().toBeFunction();
 		expectTypeOf<MyAuth["api"]["restoreSubscription"]>().toBeFunction();
+		expectTypeOf<MyAuth["api"]["upgradeSubscription"]>().toBeFunction();
+		expectTypeOf<MyAuth["api"]["createBillingPortal"]>().toBeFunction();
 	});
 });
 
-describe("stripe", async () => {
+describe("stripe", () => {
 	const mockStripe = {
 		prices: {
 			list: vi.fn().mockResolvedValue({ data: [{ id: "price_lookup_123" }] }),
@@ -95,17 +93,7 @@ describe("stripe", async () => {
 			constructEventAsync: vi.fn(),
 		},
 	};
-
 	const _stripe = mockStripe as unknown as Stripe;
-	const data = {
-		user: [],
-		session: [],
-		verification: [],
-		account: [],
-		customer: [],
-		subscription: [],
-	};
-	const memory = memoryAdapter(data);
 	const stripeOptions = {
 		stripeClient: _stripe,
 		stripeWebhookSecret: process.env.STRIPE_WEBHOOK_SECRET!,
@@ -126,36 +114,20 @@ describe("stripe", async () => {
 			],
 		},
 	} satisfies StripeOptions;
-	const auth = betterAuth({
-		database: memory,
-		baseURL: "http://localhost:3000",
-		// database: new Database(":memory:"),
-		emailAndPassword: {
-			enabled: true,
-		},
-		plugins: [stripe(stripeOptions)],
-	});
-	const ctx = await auth.$context;
-	const authClient = createAuthClient({
-		baseURL: "http://localhost:3000",
-		plugins: [
-			bearer(),
-			stripeClient({
-				subscription: true,
-			}),
-		],
-		fetchOptions: {
-			customFetchImpl: async (url, init) => {
-				return auth.handler(new Request(url, init));
-			},
-		},
-	});
 
 	const testUser = {
 		email: "test@email.com",
 		password: "password",
 		name: "Test User",
 	};
+	const data = {
+		user: [],
+		session: [],
+		verification: [],
+		account: [],
+		customer: [],
+		subscription: [],
+	};
 
 	beforeEach(() => {
 		data.user = [];
@@ -168,8 +140,24 @@ describe("stripe", async () => {
 		vi.clearAllMocks();
 	});
 
+	const memory = memoryAdapter(data);
+
 	it("should create a customer on sign up", async () => {
-		const userRes = await authClient.signUp.email(testUser, {
+		const { client, auth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
+		const userRes = await client.signUp.email(testUser, {
 			throw: true,
 		});
 		const res = await ctx.adapter.findOne<User>({
@@ -188,17 +176,31 @@ describe("stripe", async () => {
 	});
 
 	it("should create a subscription", async () => {
-		const userRes = await authClient.signUp.email(testUser, {
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
+		const userRes = await client.signUp.email(testUser, {
 			throw: true,
 		});
 
 		const headers = new Headers();
-		await authClient.signIn.email(testUser, {
+		await client.signIn.email(testUser, {
 			throw: true,
-			onSuccess: setCookieToHeader(headers),
+			onSuccess: sessionSetter(headers),
 		});
 
-		const res = await authClient.subscription.upgrade({
+		const res = await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: {
 				headers,
@@ -228,19 +230,33 @@ describe("stripe", async () => {
 	});
 
 	it("should not allow cross-user subscriptionId operations (upgrade/cancel/restore)", async () => {
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
 		const userA = {
 			email: "user-a@email.com",
 			password: "password",
 			name: "User A",
 		};
-		const userARes = await authClient.signUp.email(userA, { throw: true });
+		const userARes = await client.signUp.email(userA, { throw: true });
 
 		const userAHeaders = new Headers();
-		await authClient.signIn.email(userA, {
+		await client.signIn.email(userA, {
 			throw: true,
-			onSuccess: setCookieToHeader(userAHeaders),
+			onSuccess: sessionSetter(userAHeaders),
 		});
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers: userAHeaders },
 		});
@@ -256,11 +272,11 @@ describe("stripe", async () => {
 			password: "password",
 			name: "User B",
 		};
-		await authClient.signUp.email(userB, { throw: true });
+		await client.signUp.email(userB, { throw: true });
 		const userBHeaders = new Headers();
-		await authClient.signIn.email(userB, {
+		await client.signIn.email(userB, {
 			throw: true,
-			onSuccess: setCookieToHeader(userBHeaders),
+			onSuccess: sessionSetter(userBHeaders),
 		});
 
 		mockStripe.checkout.sessions.create.mockClear();
@@ -268,7 +284,7 @@ describe("stripe", async () => {
 		mockStripe.subscriptions.list.mockClear();
 		mockStripe.subscriptions.update.mockClear();
 
-		const upgradeRes = await authClient.subscription.upgrade({
+		const upgradeRes = await client.subscription.upgrade({
 			plan: "premium",
 			subscriptionId: userASub!.id,
 			fetchOptions: { headers: userBHeaders },
@@ -314,7 +330,21 @@ describe("stripe", async () => {
 	});
 
 	it("should list active subscriptions", async () => {
-		const userRes = await authClient.signUp.email(
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
+		const userRes = await client.signUp.email(
 			{
 				...testUser,
 				email: "list-test@email.com",
@@ -326,18 +356,18 @@ describe("stripe", async () => {
 		const userId = userRes.user.id;
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{
 				...testUser,
 				email: "list-test@email.com",
 			},
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
-		const listRes = await authClient.subscription.list({
+		const listRes = await client.subscription.list({
 			fetchOptions: {
 				headers,
 			},
@@ -345,13 +375,13 @@ describe("stripe", async () => {
 
 		expect(Array.isArray(listRes.data)).toBe(true);
 
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: {
 				headers,
 			},
 		});
-		const listBeforeActive = await authClient.subscription.list({
+		const listBeforeActive = await client.subscription.list({
 			fetchOptions: {
 				headers,
 			},
@@ -370,7 +400,7 @@ describe("stripe", async () => {
 				},
 			],
 		});
-		const listAfterRes = await authClient.subscription.list({
+		const listAfterRes = await client.subscription.list({
 			fetchOptions: {
 				headers,
 			},
@@ -379,13 +409,24 @@ describe("stripe", async () => {
 	});
 
 	it("should handle subscription webhook events", async () => {
-		const { id: testReferenceId } = await ctx.adapter.create({
+		const { auth: testAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
+		const testCtx = await testAuth.$context;
+
+		const { id: testReferenceId } = await testCtx.adapter.create({
 			model: "user",
 			data: {
 				email: "test@email.com",
 			},
 		});
-		const { id: testSubscriptionId } = await ctx.adapter.create({
+		const { id: testSubscriptionId } = await testCtx.adapter.create({
 			model: "subscription",
 			data: {
 				referenceId: testReferenceId,
@@ -442,16 +483,17 @@ describe("stripe", async () => {
 			stripeWebhookSecret: "test_secret",
 		};
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: {
-				enabled: true,
+		const { auth: webhookTestAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(testOptions)],
 			},
-			plugins: [stripe(testOptions)],
-		});
+			{
+				disableTestUser: true,
+			},
+		);
 
-		const testCtx = await testAuth.$context;
+		const webhookTestCtx = await webhookTestAuth.$context;
 
 		const mockRequest = new Request(
 			"http://localhost:3000/api/auth/stripe/webhook",
@@ -463,18 +505,19 @@ describe("stripe", async () => {
 				body: JSON.stringify(mockCheckoutSessionEvent),
 			},
 		);
-		const response = await testAuth.handler(mockRequest);
+		const response = await webhookTestAuth.handler(mockRequest);
 		expect(response.status).toBe(200);
 
-		const updatedSubscription = await testCtx.adapter.findOne<Subscription>({
-			model: "subscription",
-			where: [
-				{
-					field: "id",
-					value: testSubscriptionId,
-				},
-			],
-		});
+		const updatedSubscription =
+			await webhookTestCtx.adapter.findOne<Subscription>({
+				model: "subscription",
+				where: [
+					{
+						field: "id",
+						value: testSubscriptionId,
+					},
+				],
+			});
 
 		expect(updatedSubscription).toMatchObject({
 			id: testSubscriptionId,
@@ -486,13 +529,24 @@ describe("stripe", async () => {
 	});
 
 	it("should handle subscription webhook events with trial", async () => {
-		const { id: testReferenceId } = await ctx.adapter.create({
+		const { auth: testAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
+		const testCtx = await testAuth.$context;
+
+		const { id: testReferenceId } = await testCtx.adapter.create({
 			model: "user",
 			data: {
 				email: "test@email.com",
 			},
 		});
-		const { id: testSubscriptionId } = await ctx.adapter.create({
+		const { id: testSubscriptionId } = await testCtx.adapter.create({
 			model: "subscription",
 			data: {
 				referenceId: testReferenceId,
@@ -551,16 +605,17 @@ describe("stripe", async () => {
 			stripeWebhookSecret: "test_secret",
 		};
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: {
-				enabled: true,
+		const { auth: webhookTestAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(testOptions)],
 			},
-			plugins: [stripe(testOptions)],
-		});
+			{
+				disableTestUser: true,
+			},
+		);
 
-		const testCtx = await testAuth.$context;
+		const webhookTestCtx = await webhookTestAuth.$context;
 
 		const mockRequest = new Request(
 			"http://localhost:3000/api/auth/stripe/webhook",
@@ -572,18 +627,19 @@ describe("stripe", async () => {
 				body: JSON.stringify(mockCheckoutSessionEvent),
 			},
 		);
-		const response = await testAuth.handler(mockRequest);
+		const response = await webhookTestAuth.handler(mockRequest);
 		expect(response.status).toBe(200);
 
-		const updatedSubscription = await testCtx.adapter.findOne<Subscription>({
-			model: "subscription",
-			where: [
-				{
-					field: "id",
-					value: testSubscriptionId,
-				},
-			],
-		});
+		const updatedSubscription =
+			await webhookTestCtx.adapter.findOne<Subscription>({
+				model: "subscription",
+				where: [
+					{
+						field: "id",
+						value: testSubscriptionId,
+					},
+				],
+			});
 
 		expect(updatedSubscription).toMatchObject({
 			id: testSubscriptionId,
@@ -596,17 +652,28 @@ describe("stripe", async () => {
 		});
 	});
 
-	const { id: userId } = await ctx.adapter.create({
-		model: "user",
-		data: {
-			email: "delete-test@email.com",
-		},
-	});
-
 	it("should handle subscription deletion webhook", async () => {
+		const { auth: testAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
+		const testCtx = await testAuth.$context;
+
+		const { id: userId } = await testCtx.adapter.create({
+			model: "user",
+			data: {
+				email: "delete-test@email.com",
+			},
+		});
+
 		const subId = "test_sub_delete";
 
-		await ctx.adapter.create({
+		await testCtx.adapter.create({
 			model: "subscription",
 			data: {
 				referenceId: userId,
@@ -617,7 +684,7 @@ describe("stripe", async () => {
 			},
 		});
 
-		const subscription = await ctx.adapter.findOne<Subscription>({
+		const subscription = await testCtx.adapter.findOne<Subscription>({
 			model: "subscription",
 			where: [
 				{
@@ -661,14 +728,17 @@ describe("stripe", async () => {
 			stripeWebhookSecret: "test_secret",
 		};
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			emailAndPassword: {
-				enabled: true,
+		const { auth: webhookTestAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(testOptions)],
 			},
-			database: memory,
-			plugins: [stripe(testOptions)],
-		});
+			{
+				disableTestUser: true,
+			},
+		);
+
+		const webhookTestCtx = await webhookTestAuth.$context;
 
 		const mockRequest = new Request(
 			"http://localhost:3000/api/auth/stripe/webhook",
@@ -681,24 +751,43 @@ describe("stripe", async () => {
 			},
 		);
 
-		const response = await testAuth.handler(mockRequest);
+		const response = await webhookTestAuth.handler(mockRequest);
 		expect(response.status).toBe(200);
 
 		if (subscription) {
-			const updatedSubscription = await ctx.adapter.findOne<Subscription>({
-				model: "subscription",
-				where: [
-					{
-						field: "id",
-						value: subscription.id,
-					},
-				],
-			});
+			const updatedSubscription =
+				await webhookTestCtx.adapter.findOne<Subscription>({
+					model: "subscription",
+					where: [
+						{
+							field: "id",
+							value: subscription.id,
+						},
+					],
+				});
 			expect(updatedSubscription?.status).toBe("canceled");
 		}
 	});
 
 	it("should execute subscription event handlers", async () => {
+		const { auth: testAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
+		const testCtx = await testAuth.$context;
+
+		const { id: userId } = await testCtx.adapter.create({
+			model: "user",
+			data: {
+				email: "event-handler-test@email.com",
+			},
+		});
+
 		const onSubscriptionComplete = vi.fn();
 		const onSubscriptionUpdate = vi.fn();
 		const onSubscriptionCancel = vi.fn();
@@ -755,14 +844,19 @@ describe("stripe", async () => {
 			stripeClient: mockStripeForEvents as unknown as Stripe,
 		};
 
-		const eventTestAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: { enabled: true },
-			plugins: [stripe(eventTestOptions)],
-		});
+		const { auth: eventTestAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(eventTestOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
 
-		const { id: testSubscriptionId } = await ctx.adapter.create({
+		const eventTestCtx = await eventTestAuth.$context;
+
+		const { id: testSubscriptionId } = await eventTestCtx.adapter.create({
 			model: "subscription",
 			data: {
 				referenceId: userId,
@@ -945,25 +1039,6 @@ describe("stripe", async () => {
 	it("should return updated subscription in onSubscriptionUpdate callback", async () => {
 		const onSubscriptionUpdate = vi.fn();
 
-		const { id: testReferenceId } = await ctx.adapter.create({
-			model: "user",
-			data: {
-				email: "update-callback@email.com",
-			},
-		});
-
-		const { id: testSubscriptionId } = await ctx.adapter.create({
-			model: "subscription",
-			data: {
-				referenceId: testReferenceId,
-				stripeCustomerId: "cus_update_test",
-				stripeSubscriptionId: "sub_update_test",
-				status: "active",
-				plan: "starter",
-				seats: 1,
-			},
-		});
-
 		// Simulate subscription update event (e.g., seat change from 1 to 5)
 		const updateEvent = {
 			type: "customer.subscription.updated",
@@ -1006,13 +1081,35 @@ describe("stripe", async () => {
 			},
 		} as unknown as StripeOptions;
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: {
-				enabled: true,
+		const { auth: testAuth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(testOptions)],
+			},
+			{
+				disableTestUser: true,
+			},
+		);
+
+		const ctx = await testAuth.$context;
+
+		const { id: testReferenceId } = await ctx.adapter.create({
+			model: "user",
+			data: {
+				email: "update-callback@email.com",
+			},
+		});
+
+		const { id: testSubscriptionId } = await ctx.adapter.create({
+			model: "subscription",
+			data: {
+				referenceId: testReferenceId,
+				stripeCustomerId: "cus_update_test",
+				stripeSubscriptionId: "sub_update_test",
+				status: "active",
+				plan: "starter",
+				seats: 1,
 			},
-			plugins: [stripe(testOptions)],
 		});
 
 		const mockRequest = new Request(
@@ -1050,7 +1147,21 @@ describe("stripe", async () => {
 	});
 
 	it("should allow seat upgrades for the same plan", async () => {
-		const userRes = await authClient.signUp.email(
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
+		const userRes = await client.signUp.email(
 			{
 				...testUser,
 				email: "seat-upgrade@email.com",
@@ -1061,18 +1172,18 @@ describe("stripe", async () => {
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{
 				...testUser,
 				email: "seat-upgrade@email.com",
 			},
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			seats: 1,
 			fetchOptions: {
@@ -1093,7 +1204,7 @@ describe("stripe", async () => {
 			],
 		});
 
-		const upgradeRes = await authClient.subscription.upgrade({
+		const upgradeRes = await client.subscription.upgrade({
 			plan: "starter",
 			seats: 5,
 			fetchOptions: {
@@ -1105,7 +1216,21 @@ describe("stripe", async () => {
 	});
 
 	it("should prevent duplicate subscriptions with same plan and same seats", async () => {
-		const userRes = await authClient.signUp.email(
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
+		const userRes = await client.signUp.email(
 			{
 				...testUser,
 				email: "duplicate-prevention@email.com",
@@ -1116,18 +1241,18 @@ describe("stripe", async () => {
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{
 				...testUser,
 				email: "duplicate-prevention@email.com",
 			},
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			seats: 3,
 			fetchOptions: {
@@ -1149,7 +1274,7 @@ describe("stripe", async () => {
 			],
 		});
 
-		const upgradeRes = await authClient.subscription.upgrade({
+		const upgradeRes = await client.subscription.upgrade({
 			plan: "starter",
 			seats: 3,
 			fetchOptions: {
@@ -1162,21 +1287,34 @@ describe("stripe", async () => {
 	});
 
 	it("should only call Stripe customers.create once for signup and upgrade", async () => {
-		await authClient.signUp.email(
+		const { client, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+
+		await client.signUp.email(
 			{ ...testUser, email: "single-create@email.com" },
 			{ throw: true },
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{ ...testUser, email: "single-create@email.com" },
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1185,7 +1323,20 @@ describe("stripe", async () => {
 	});
 
 	it("should create billing portal session", async () => {
-		await authClient.signUp.email(
+		const { client, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+
+		await client.signUp.email(
 			{
 				...testUser,
 				email: "billing-portal@email.com",
@@ -1196,17 +1347,17 @@ describe("stripe", async () => {
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{
 				...testUser,
 				email: "billing-portal@email.com",
 			},
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
-		const billingPortalRes = await authClient.subscription.billingPortal({
+		const billingPortalRes = await client.subscription.billingPortal({
 			returnUrl: "/dashboard",
 			fetchOptions: {
 				headers,
@@ -1233,36 +1384,37 @@ describe("stripe", async () => {
 			},
 		} as unknown as StripeOptions;
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: { enabled: true },
-			plugins: [stripe(testOptions)],
-		});
+		const {
+			auth: testAuth,
+			client: testClient,
+			sessionSetter: testSessionSetter,
+		} = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(testOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
 		const testCtx = await testAuth.$context;
 
-		const testAuthClient = createAuthClient({
-			baseURL: "http://localhost:3000",
-			plugins: [bearer(), stripeClient({ subscription: true })],
-			fetchOptions: {
-				customFetchImpl: async (url, init) =>
-					testAuth.handler(new Request(url, init)),
-			},
-		});
-
 		// Sign up and sign in the user
-		const userRes = await testAuthClient.signUp.email(
+		const userRes = await testClient.signUp.email(
 			{ ...testUser, email: "org-ref@email.com" },
 			{ throw: true },
 		);
 		const headers = new Headers();
-		await testAuthClient.signIn.email(
+		await testClient.signIn.email(
 			{ ...testUser, email: "org-ref@email.com" },
-			{ throw: true, onSuccess: setCookieToHeader(headers) },
+			{ throw: true, onSuccess: testSessionSetter(headers) },
 		);
 
 		// Create a personal subscription (referenceId = user id)
-		await testAuthClient.subscription.upgrade({
+		await testClient.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1301,14 +1453,12 @@ describe("stripe", async () => {
 		});
 
 		// Attempt to upgrade using an org referenceId
-		const upgradeRes = await testAuthClient.subscription.upgrade({
+		const upgradeRes = await testClient.subscription.upgrade({
 			plan: "starter",
 			referenceId: orgId,
 			fetchOptions: { headers },
 		});
-		console.log(upgradeRes);
-
-		// // It should NOT go through billing portal (which would update the personal sub)
+		// It should NOT go through billing portal (which would update the personal sub)
 		expect(mockStripe.billingPortal.sessions.create).not.toHaveBeenCalled();
 		expect(upgradeRes.data?.url).toBeDefined();
 
@@ -1330,23 +1480,37 @@ describe("stripe", async () => {
 	});
 
 	it("should prevent multiple free trials for the same user", async () => {
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
 		// Create a user
-		const userRes = await authClient.signUp.email(
+		const userRes = await client.signUp.email(
 			{ ...testUser, email: "trial-prevention@email.com" },
 			{ throw: true },
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{ ...testUser, email: "trial-prevention@email.com" },
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
 		// First subscription with trial
-		const firstUpgradeRes = await authClient.subscription.upgrade({
+		const firstUpgradeRes = await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1384,7 +1548,7 @@ describe("stripe", async () => {
 		});
 
 		// Try to subscribe again - should NOT get a trial
-		const secondUpgradeRes = await authClient.subscription.upgrade({
+		const secondUpgradeRes = await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1418,18 +1582,32 @@ describe("stripe", async () => {
 		// Reset mocks for this test
 		vi.clearAllMocks();
 
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
 		// Create a user
-		const userRes = await authClient.signUp.email(
+		const userRes = await client.signUp.email(
 			{ ...testUser, email: "upgrade-existing@email.com" },
 			{ throw: true },
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{ ...testUser, email: "upgrade-existing@email.com" },
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
@@ -1439,7 +1617,7 @@ describe("stripe", async () => {
 		});
 
 		// First create a starter subscription
-		await authClient.subscription.upgrade({
+		await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1511,7 +1689,7 @@ describe("stripe", async () => {
 		mockStripe.billingPortal.sessions.create.mockClear();
 
 		// Now upgrade to premium plan - should use billing portal to update existing subscription
-		const upgradeRes = await authClient.subscription.upgrade({
+		const upgradeRes = await client.subscription.upgrade({
 			plan: "premium",
 			fetchOptions: { headers },
 		});
@@ -1550,23 +1728,37 @@ describe("stripe", async () => {
 	});
 
 	it("should prevent multiple free trials across different plans", async () => {
+		const { client, auth, sessionSetter } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
 		// Create a user
-		const userRes = await authClient.signUp.email(
+		const userRes = await client.signUp.email(
 			{ ...testUser, email: "cross-plan-trial@email.com" },
 			{ throw: true },
 		);
 
 		const headers = new Headers();
-		await authClient.signIn.email(
+		await client.signIn.email(
 			{ ...testUser, email: "cross-plan-trial@email.com" },
 			{
 				throw: true,
-				onSuccess: setCookieToHeader(headers),
+				onSuccess: sessionSetter(headers),
 			},
 		);
 
 		// First subscription with trial on starter plan
-		const firstUpgradeRes = await authClient.subscription.upgrade({
+		const firstUpgradeRes = await client.subscription.upgrade({
 			plan: "starter",
 			fetchOptions: { headers },
 		});
@@ -1604,7 +1796,7 @@ describe("stripe", async () => {
 		});
 
 		// Try to subscribe to a different plan - should NOT get a trial
-		const secondUpgradeRes = await authClient.subscription.upgrade({
+		const secondUpgradeRes = await client.subscription.upgrade({
 			plan: "premium",
 			fetchOptions: { headers },
 		});
@@ -1643,6 +1835,20 @@ describe("stripe", async () => {
 	});
 
 	it("should update stripe customer email when user email changes", async () => {
+		const { client, auth } = await getTestInstance(
+			{
+				database: memory,
+				plugins: [stripe(stripeOptions)],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
+				},
+			},
+		);
+		const ctx = await auth.$context;
+
 		// Setup mock for customer retrieve and update
 		mockStripe.customers.retrieve = vi.fn().mockResolvedValue({
 			id: "cus_mock123",
@@ -1655,7 +1861,7 @@ describe("stripe", async () => {
 		});
 
 		// Sign up a user
-		const userRes = await authClient.signUp.email(testUser, {
+		const userRes = await client.signUp.email(testUser, {
 			throw: true,
 		});
 
@@ -1685,11 +1891,14 @@ describe("stripe", async () => {
 		});
 
 		// Update the user's email using internal adapter (which triggers hooks)
-		const endpointCtx = { context: ctx } as GenericEndpointContext;
-		await runWithEndpointContext(endpointCtx, () =>
-			ctx.internalAdapter.updateUserByEmail(testUser.email, {
-				email: "newemail@example.com",
-			}),
+		await runWithEndpointContext(
+			{
+				context: ctx,
+			},
+			() =>
+				ctx.internalAdapter.updateUserByEmail(testUser.email, {
+					email: "newemail@example.com",
+				}),
 		);
 
 		// Verify that Stripe customer.retrieve was called
@@ -1713,26 +1922,21 @@ describe("stripe", async () => {
 				getCustomerCreateParams: getCustomerCreateParamsMock,
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: {
-					enabled: true,
+			const { client: testClient } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
 				},
-				plugins: [stripe(testOptions)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
 				},
-			});
+			);
 
 			// Sign up a user
-			const userRes = await testAuthClient.signUp.email(
+			const userRes = await testClient.signUp.email(
 				{
 					email: "custom-params@email.com",
 					password: "password",
@@ -1785,23 +1989,18 @@ describe("stripe", async () => {
 				getCustomerCreateParams: getCustomerCreateParamsMock,
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: {
-					enabled: true,
+			const { client: testAuthClient } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
 				},
-				plugins: [stripe(testOptions)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
 				},
-			});
+			);
 
 			// Sign up a user
 			await testAuthClient.signUp.email(
@@ -1849,23 +2048,18 @@ describe("stripe", async () => {
 				getCustomerCreateParams: getCustomerCreateParamsMock,
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: {
-					enabled: true,
+			const { client: testAuthClient } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
 				},
-				plugins: [stripe(testOptions)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
 				},
-			});
+			);
 
 			// Sign up a user
 			const userRes = await testAuthClient.signUp.email(
@@ -1903,23 +2097,18 @@ describe("stripe", async () => {
 				// No getCustomerCreateParams provided
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: {
-					enabled: true,
+			const { client: testAuthClient } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
 				},
-				plugins: [stripe(testOptions)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
 				},
-			});
+			);
 
 			// Sign up a user
 			const userRes = await testAuthClient.signUp.email(
@@ -1960,12 +2149,15 @@ describe("stripe", async () => {
 				stripeWebhookSecret: "test_secret",
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions)],
-			});
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
 
 			const mockRequest = new Request(
 				"http://localhost:3000/api/auth/stripe/webhook",
@@ -1985,12 +2177,15 @@ describe("stripe", async () => {
 		});
 
 		it("should reject webhook request without stripe-signature header", async () => {
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(stripeOptions)],
-			});
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(stripeOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
 
 			const mockRequest = new Request(
 				"http://localhost:3000/api/auth/stripe/webhook",
@@ -2023,12 +2218,15 @@ describe("stripe", async () => {
 				stripeWebhookSecret: "test_secret",
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions)],
-			});
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
 
 			const mockRequest = new Request(
 				"http://localhost:3000/api/auth/stripe/webhook",
@@ -2086,14 +2284,18 @@ describe("stripe", async () => {
 				},
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions as StripeOptions)],
-			});
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions as StripeOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
+			const testCtx = await testAuth.$context;
 
-			await ctx.adapter.create({
+			await testCtx.adapter.create({
 				model: "subscription",
 				data: {
 					referenceId: "user_123",
@@ -2165,17 +2367,28 @@ describe("stripe", async () => {
 				stripeWebhookSecret: "test_secret_async",
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions)],
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
+			const testCtx = await testAuth.$context;
+
+			const { id: testUserId } = await testCtx.adapter.create({
+				model: "user",
+				data: {
+					email: "async-test@email.com",
+				},
 			});
 
-			await ctx.adapter.create({
+			await testCtx.adapter.create({
 				model: "subscription",
 				data: {
-					referenceId: userId,
+					referenceId: testUserId,
 					stripeCustomerId: "cus_test_async",
 					stripeSubscriptionId: "sub_test_async",
 					status: "incomplete",
@@ -2231,12 +2444,15 @@ describe("stripe", async () => {
 				stripeWebhookSecret: "test_secret_params",
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions)],
-			});
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
 
 			const mockRequest = new Request(
 				"http://localhost:3000/api/auth/stripe/webhook",
@@ -2307,17 +2523,28 @@ describe("stripe", async () => {
 				stripeWebhookSecret: "test_secret_v18",
 			};
 
-			const testAuth = betterAuth({
-				baseURL: "http://localhost:3000",
-				database: memory,
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptions)],
+			const { auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptions)],
+				},
+				{
+					disableTestUser: true,
+				},
+			);
+			const testCtx = await testAuth.$context;
+
+			const { id: testUserId } = await testCtx.adapter.create({
+				model: "user",
+				data: {
+					email: "v18-test@email.com",
+				},
 			});
 
-			await ctx.adapter.create({
+			await testCtx.adapter.create({
 				model: "subscription",
 				data: {
-					referenceId: userId,
+					referenceId: testUserId,
 					stripeCustomerId: "cus_test_v18",
 					stripeSubscriptionId: "sub_test_v18",
 					status: "incomplete",
@@ -2376,30 +2603,31 @@ describe("stripe", async () => {
 			},
 		];
 
-		const testAuth = betterAuth({
-			baseURL: "http://localhost:3000",
-			database: memory,
-			emailAndPassword: { enabled: true },
-			plugins: [
-				stripe({
-					...stripeOptions,
-					subscription: {
-						enabled: true,
-						plans: flexiblePlans,
-					},
-				}),
-			],
-		});
-
-		const testClient = createAuthClient({
-			baseURL: "http://localhost:3000",
-			plugins: [bearer(), stripeClient({ subscription: true })],
-			fetchOptions: {
-				customFetchImpl: async (url, init) => {
-					return testAuth.handler(new Request(url, init));
+		const {
+			client: testClient,
+			auth: testAuth,
+			sessionSetter: testSessionSetter,
+		} = await getTestInstance(
+			{
+				database: memory,
+				plugins: [
+					stripe({
+						...stripeOptions,
+						subscription: {
+							enabled: true,
+							plans: flexiblePlans,
+						},
+					}),
+				],
+			},
+			{
+				disableTestUser: true,
+				clientOptions: {
+					plugins: [stripeClient({ subscription: true })],
 				},
 			},
-		});
+		);
+		const testCtx = await testAuth.$context;
 
 		// Create user and sign in
 		const headers = new Headers();
@@ -2407,18 +2635,18 @@ describe("stripe", async () => {
 			{ email: "limits@test.com", password: "password", name: "Test" },
 			{ throw: true },
 		);
-		const userId = userRes.user.id;
+		const limitUserId = userRes.user.id;
 
 		await testClient.signIn.email(
 			{ email: "limits@test.com", password: "password" },
-			{ throw: true, onSuccess: setCookieToHeader(headers) },
+			{ throw: true, onSuccess: testSessionSetter(headers) },
 		);
 
 		// Create subscription
-		await ctx.adapter.create({
+		await testCtx.adapter.create({
 			model: "subscription",
 			data: {
-				referenceId: userId,
+				referenceId: limitUserId,
 				stripeCustomerId: "cus_limits_test",
 				stripeSubscriptionId: "sub_limits_test",
 				status: "active",
@@ -2477,21 +2705,19 @@ describe("stripe", async () => {
 				createCustomerOnSignUp: true,
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptionsWithHook)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+			const { client: testAuthClient, auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptionsWithHook)],
 				},
-			});
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
+				},
+			);
+			const testCtx = await testAuth.$context;
 
 			vi.clearAllMocks();
 
@@ -2515,7 +2741,7 @@ describe("stripe", async () => {
 			expect(mockStripe.customers.create).not.toHaveBeenCalled();
 
 			// Verify user has the EXISTING Stripe customer ID (not new duplicate)
-			const user = await ctx.adapter.findOne<
+			const user = await testCtx.adapter.findOne<
 				User & { stripeCustomerId?: string }
 			>({
 				model: "user",
@@ -2541,21 +2767,19 @@ describe("stripe", async () => {
 				createCustomerOnSignUp: true,
 			} satisfies StripeOptions;
 
-			const testAuth = betterAuth({
-				database: memory,
-				baseURL: "http://localhost:3000",
-				emailAndPassword: { enabled: true },
-				plugins: [stripe(testOptionsWithHook)],
-			});
-
-			const testAuthClient = createAuthClient({
-				baseURL: "http://localhost:3000",
-				plugins: [bearer(), stripeClient({ subscription: true })],
-				fetchOptions: {
-					customFetchImpl: async (url, init) =>
-						testAuth.handler(new Request(url, init)),
+			const { client: testAuthClient, auth: testAuth } = await getTestInstance(
+				{
+					database: memory,
+					plugins: [stripe(testOptionsWithHook)],
 				},
-			});
+				{
+					disableTestUser: true,
+					clientOptions: {
+						plugins: [stripeClient({ subscription: true })],
+					},
+				},
+			);
+			const testCtx = await testAuth.$context;
 
 			vi.clearAllMocks();
 
@@ -2586,7 +2810,7 @@ describe("stripe", async () => {
 			});
 
 			// Verify user has the new Stripe customer ID
-			const user = await ctx.adapter.findOne<
+			const user = await testCtx.adapter.findOne<
 				User & { stripeCustomerId?: string }
 			>({
 				model: "user",