chore: migrate tests from tests-ui/ to colocate with source files (#7811)

## Summary

Migrates all unit tests from `tests-ui/` to colocate with their source
files in `src/`, improving discoverability and maintainability.

## Changes

- **What**: Relocated all unit tests to be adjacent to the code they
test, following the `<source>.test.ts` naming convention
- **Config**: Updated `vitest.config.ts` to remove `tests-ui` include
pattern and `@tests-ui` alias
- **Docs**: Moved testing documentation to `docs/testing/` with updated
paths and patterns

## Review Focus

- Migration patterns documented in
`temp/plans/migrate-tests-ui-to-src.md`
- Tests use `@/` path aliases instead of relative imports
- Shared fixtures placed in `__fixtures__/` directories

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7811-chore-migrate-tests-from-tests-ui-to-colocate-with-source-files-2da6d73d36508147a4cce85365dee614)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>

src/platform/cloud/subscription/components/PricingTable.test.ts

@@ -0,0 +1,235 @@
+import { createTestingPinia } from '@pinia/testing'
+import { flushPromises, mount } from '@vue/test-utils'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { computed, ref } from 'vue'
+import { createI18n } from 'vue-i18n'
+
+import PricingTable from '@/platform/cloud/subscription/components/PricingTable.vue'
+import Button from '@/components/ui/button/Button.vue'
+
+const mockIsActiveSubscription = ref(false)
+const mockSubscriptionTier = ref<
+  'STANDARD' | 'CREATOR' | 'PRO' | 'FOUNDERS_EDITION' | null
+>(null)
+const mockIsYearlySubscription = ref(false)
+const mockAccessBillingPortal = vi.fn()
+const mockReportError = vi.fn()
+const mockGetAuthHeader = vi.fn(() =>
+  Promise.resolve({ Authorization: 'Bearer test-token' })
+)
+
+vi.mock('@/platform/cloud/subscription/composables/useSubscription', () => ({
+  useSubscription: () => ({
+    isActiveSubscription: computed(() => mockIsActiveSubscription.value),
+    subscriptionTier: computed(() => mockSubscriptionTier.value),
+    isYearlySubscription: computed(() => mockIsYearlySubscription.value)
+  })
+}))
+
+vi.mock('@/composables/auth/useFirebaseAuthActions', () => ({
+  useFirebaseAuthActions: () => ({
+    accessBillingPortal: mockAccessBillingPortal,
+    reportError: mockReportError
+  })
+}))
+
+vi.mock('@/composables/useErrorHandling', () => ({
+  useErrorHandling: () => ({
+    wrapWithErrorHandlingAsync: vi.fn(
+      (fn, errorHandler) =>
+        async (...args: unknown[]) => {
+          try {
+            return await fn(...args)
+          } catch (error) {
+            if (errorHandler) {
+              errorHandler(error)
+            }
+            throw error
+          }
+        }
+    )
+  })
+}))
+
+vi.mock('@/stores/firebaseAuthStore', () => ({
+  useFirebaseAuthStore: () => ({
+    getAuthHeader: mockGetAuthHeader
+  }),
+  FirebaseAuthStoreError: class extends Error {}
+}))
+
+vi.mock('@/platform/distribution/types', () => ({
+  isCloud: true
+}))
+
+global.fetch = vi.fn()
+
+const i18n = createI18n({
+  legacy: false,
+  locale: 'en',
+  messages: {
+    en: {
+      subscription: {
+        yearly: 'Yearly',
+        monthly: 'Monthly',
+        mostPopular: 'Most Popular',
+        usdPerMonth: '/ month',
+        billedYearly: 'Billed yearly ({total})',
+        billedMonthly: 'Billed monthly',
+        currentPlan: 'Current Plan',
+        subscribeTo: 'Subscribe to {plan}',
+        changeTo: 'Change to {plan}',
+        maxDuration: {
+          standard: '30 min',
+          creator: '30 min',
+          pro: '1 hr'
+        },
+        tiers: {
+          standard: { name: 'Standard' },
+          creator: { name: 'Creator' },
+          pro: { name: 'Pro' }
+        },
+        benefits: {
+          monthlyCredits: '{credits} monthly credits',
+          maxDuration: '{duration} max duration',
+          gpu: 'RTX 6000 Pro GPU',
+          addCredits: 'Add more credits anytime',
+          customLoRAs: 'Import custom LoRAs'
+        }
+      }
+    }
+  }
+})
+
+function createWrapper() {
+  return mount(PricingTable, {
+    global: {
+      plugins: [createTestingPinia({ createSpy: vi.fn }), i18n],
+      components: {
+        Button
+      },
+      stubs: {
+        SelectButton: {
+          template: '<div><slot /></div>',
+          props: ['modelValue', 'options'],
+          emits: ['update:modelValue']
+        },
+        Popover: { template: '<div><slot /></div>' }
+      }
+    }
+  })
+}
+
+describe('PricingTable', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockIsActiveSubscription.value = false
+    mockSubscriptionTier.value = null
+    mockIsYearlySubscription.value = false
+    vi.mocked(global.fetch).mockResolvedValue({
+      ok: true,
+      json: async () => ({ checkout_url: 'https://checkout.stripe.com/test' })
+    } as Response)
+  })
+
+  describe('billing portal deep linking', () => {
+    it('should call accessBillingPortal with yearly tier suffix when billing cycle is yearly (default)', async () => {
+      mockIsActiveSubscription.value = true
+      mockSubscriptionTier.value = 'STANDARD'
+
+      const wrapper = createWrapper()
+      await flushPromises()
+
+      const creatorButton = wrapper
+        .findAll('button')
+        .find((btn) => btn.text().includes('Creator'))
+
+      expect(creatorButton).toBeDefined()
+      await creatorButton?.trigger('click')
+      await flushPromises()
+
+      expect(mockAccessBillingPortal).toHaveBeenCalledWith('creator-yearly')
+    })
+
+    it('should call accessBillingPortal with different tiers correctly', async () => {
+      mockIsActiveSubscription.value = true
+      mockSubscriptionTier.value = 'STANDARD'
+
+      const wrapper = createWrapper()
+      await flushPromises()
+
+      const proButton = wrapper
+        .findAll('button')
+        .find((btn) => btn.text().includes('Pro'))
+
+      await proButton?.trigger('click')
+      await flushPromises()
+
+      expect(mockAccessBillingPortal).toHaveBeenCalledWith('pro-yearly')
+    })
+
+    it('should not call accessBillingPortal when clicking current plan', async () => {
+      mockIsActiveSubscription.value = true
+      mockSubscriptionTier.value = 'CREATOR'
+
+      const wrapper = createWrapper()
+      await flushPromises()
+
+      const currentPlanButton = wrapper
+        .findAll('button')
+        .find((btn) => btn.text().includes('Current Plan'))
+
+      await currentPlanButton?.trigger('click')
+      await flushPromises()
+
+      expect(mockAccessBillingPortal).not.toHaveBeenCalled()
+    })
+
+    it('should initiate checkout instead of billing portal for new subscribers', async () => {
+      mockIsActiveSubscription.value = false
+
+      const windowOpenSpy = vi
+        .spyOn(window, 'open')
+        .mockImplementation(() => null)
+
+      const wrapper = createWrapper()
+      await flushPromises()
+
+      const subscribeButton = wrapper
+        .findAll('button')
+        .find((btn) => btn.text().includes('Subscribe'))
+
+      await subscribeButton?.trigger('click')
+      await flushPromises()
+
+      expect(mockAccessBillingPortal).not.toHaveBeenCalled()
+      expect(global.fetch).toHaveBeenCalledWith(
+        expect.stringContaining('/customers/cloud-subscription-checkout/'),
+        expect.any(Object)
+      )
+      expect(windowOpenSpy).toHaveBeenCalledWith(
+        'https://checkout.stripe.com/test',
+        '_blank'
+      )
+
+      windowOpenSpy.mockRestore()
+    })
+
+    it('should pass correct tier for each subscription level', async () => {
+      mockIsActiveSubscription.value = true
+      mockSubscriptionTier.value = 'PRO'
+
+      const wrapper = createWrapper()
+      await flushPromises()
+
+      const standardButton = wrapper
+        .findAll('button')
+        .find((btn) => btn.text().includes('Standard'))
+
+      await standardButton?.trigger('click')
+      await flushPromises()
+
+      expect(mockAccessBillingPortal).toHaveBeenCalledWith('standard-yearly')
+    })
+  })
+})