feat(billing): implement robust in-app subscription cancellation & fix CI/CD socket port typo

memento-note/tests/unit/billing-cancel.test.ts

@@ -0,0 +1,136 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// Mock the dependencies before importing the function
+vi.mock('@/lib/prisma', () => ({
+  prisma: {
+    subscription: {
+      findUnique: vi.fn(),
+      update: vi.fn(),
+    },
+  },
+}));
+
+vi.mock('@/lib/stripe', () => ({
+  stripe: {
+    subscriptions: {
+      update: vi.fn(),
+    },
+  },
+}));
+
+import { cancelSubscription } from '@/lib/billing/cancel-subscription';
+import { prisma } from '@/lib/prisma';
+import { stripe } from '@/lib/stripe';
+
+describe('cancelSubscription', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('should return error when userId is missing', async () => {
+    const result = await cancelSubscription('');
+    expect(result).toEqual({ success: false, error: 'User ID is required' });
+    expect(prisma.subscription.findUnique).not.toHaveBeenCalled();
+  });
+
+  it('should return error when no subscription is found in db', async () => {
+    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(null);
+
+    const result = await cancelSubscription('user_123');
+    expect(result).toEqual({ success: false, error: 'No active subscription found' });
+    expect(prisma.subscription.findUnique).toHaveBeenCalledWith({
+      where: { userId: 'user_123' },
+    });
+    expect(stripe.subscriptions.update).not.toHaveBeenCalled();
+    expect(prisma.subscription.update).not.toHaveBeenCalled();
+  });
+
+  it('should cancel subscription in Stripe and update DB successfully', async () => {
+    const mockDbSub = {
+      userId: 'user_123',
+      stripeSubscriptionId: 'sub_stripe_123',
+      currentPeriodEnd: new Date(1702678400 * 1000),
+    };
+    const mockStripeSub = {
+      id: 'sub_stripe_123',
+      canceled_at: 1700100000,
+      current_period_end: 1702678400,
+    };
+
+    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
+    vi.mocked(stripe.subscriptions.update).mockResolvedValue(mockStripeSub as any);
+    vi.mocked(prisma.subscription.update).mockResolvedValue({} as any);
+
+    const result = await cancelSubscription('user_123');
+    
+    expect(result).toEqual({ success: true });
+    expect(stripe.subscriptions.update).toHaveBeenCalledWith('sub_stripe_123', {
+      cancel_at_period_end: true,
+    });
+    expect(prisma.subscription.update).toHaveBeenCalledWith({
+      where: { userId: 'user_123' },
+      data: expect.objectContaining({
+        cancelAtPeriodEnd: true,
+        canceledAt: expect.any(Date),
+        currentPeriodEnd: expect.any(Date),
+      }),
+    });
+  });
+
+  it('should support local / mock mode cancel when stripeSubscriptionId is missing', async () => {
+    const mockDbSub = {
+      userId: 'user_123',
+      stripeSubscriptionId: null,
+    };
+
+    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
+    vi.mocked(prisma.subscription.update).mockResolvedValue({} as any);
+
+    const result = await cancelSubscription('user_123');
+
+    expect(result).toEqual({ success: true });
+    expect(stripe.subscriptions.update).not.toHaveBeenCalled();
+    expect(prisma.subscription.update).toHaveBeenCalledWith({
+      where: { userId: 'user_123' },
+      data: expect.objectContaining({
+        cancelAtPeriodEnd: true,
+        canceledAt: expect.any(Date),
+      }),
+    });
+  });
+
+  it('should return error when Stripe API call fails', async () => {
+    const mockDbSub = {
+      userId: 'user_123',
+      stripeSubscriptionId: 'sub_stripe_123',
+    };
+
+    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
+    vi.mocked(stripe.subscriptions.update).mockRejectedValue(new Error('Stripe connection error'));
+
+    const result = await cancelSubscription('user_123');
+
+    expect(result).toEqual({ success: false, error: 'Stripe connection error' });
+    expect(prisma.subscription.update).not.toHaveBeenCalled();
+  });
+
+  it('should return error when database write fails', async () => {
+    const mockDbSub = {
+      userId: 'user_123',
+      stripeSubscriptionId: 'sub_stripe_123',
+    };
+    const mockStripeSub = {
+      id: 'sub_stripe_123',
+      canceled_at: 1700100000,
+      current_period_end: 1702678400,
+    };
+
+    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
+    vi.mocked(stripe.subscriptions.update).mockResolvedValue(mockStripeSub as any);
+    vi.mocked(prisma.subscription.update).mockRejectedValue(new Error('Prisma database error'));
+
+    const result = await cancelSubscription('user_123');
+
+    expect(result).toEqual({ success: false, error: 'Prisma database error' });
+  });
+});