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/base/common/downloadUtil.test.ts

@@ -0,0 +1,199 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { downloadFile } from '@/base/common/downloadUtil'
+
+let mockIsCloud = false
+
+vi.mock('@/platform/distribution/types', () => ({
+  get isCloud() {
+    return mockIsCloud
+  }
+}))
+
+// Global stubs
+const createObjectURLSpy = vi
+  .spyOn(URL, 'createObjectURL')
+  .mockReturnValue('blob:mock-url')
+const revokeObjectURLSpy = vi
+  .spyOn(URL, 'revokeObjectURL')
+  .mockImplementation(() => {})
+
+describe('downloadUtil', () => {
+  let mockLink: HTMLAnchorElement
+  let fetchMock: ReturnType<typeof vi.fn>
+
+  beforeEach(() => {
+    mockIsCloud = false
+    fetchMock = vi.fn()
+    vi.stubGlobal('fetch', fetchMock)
+    createObjectURLSpy.mockClear().mockReturnValue('blob:mock-url')
+    revokeObjectURLSpy.mockClear().mockImplementation(() => {})
+    // Create a mock anchor element
+    mockLink = {
+      href: '',
+      download: '',
+      click: vi.fn(),
+      style: { display: '' }
+    } as unknown as HTMLAnchorElement
+
+    // Spy on DOM methods
+    vi.spyOn(document, 'createElement').mockReturnValue(mockLink)
+    vi.spyOn(document.body, 'appendChild').mockImplementation(() => mockLink)
+    vi.spyOn(document.body, 'removeChild').mockImplementation(() => mockLink)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  describe('downloadFile', () => {
+    it('should create and trigger download with basic URL', () => {
+      const testUrl = 'https://example.com/image.png'
+
+      downloadFile(testUrl)
+
+      expect(document.createElement).toHaveBeenCalledWith('a')
+      expect(mockLink.href).toBe(testUrl)
+      expect(mockLink.download).toBe('download.png') // Default filename
+      expect(document.body.appendChild).toHaveBeenCalledWith(mockLink)
+      expect(mockLink.click).toHaveBeenCalled()
+      expect(document.body.removeChild).toHaveBeenCalledWith(mockLink)
+      expect(fetchMock).not.toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should use custom filename when provided', () => {
+      const testUrl = 'https://example.com/image.png'
+      const customFilename = 'my-custom-image.png'
+
+      downloadFile(testUrl, customFilename)
+
+      expect(mockLink.href).toBe(testUrl)
+      expect(mockLink.download).toBe(customFilename)
+      expect(fetchMock).not.toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should extract filename from URL query parameters', () => {
+      const testUrl =
+        'https://example.com/api/file?filename=extracted-image.jpg&other=param'
+
+      downloadFile(testUrl)
+
+      expect(mockLink.href).toBe(testUrl)
+      expect(mockLink.download).toBe('extracted-image.jpg')
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should use default filename when URL has no filename parameter', () => {
+      const testUrl = 'https://example.com/api/file?other=param'
+
+      downloadFile(testUrl)
+
+      expect(mockLink.href).toBe(testUrl)
+      expect(mockLink.download).toBe('download.png')
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should handle invalid URLs gracefully', () => {
+      const invalidUrl = 'not-a-valid-url'
+
+      downloadFile(invalidUrl)
+
+      expect(mockLink.href).toBe(invalidUrl)
+      expect(mockLink.download).toBe('download.png')
+      expect(mockLink.click).toHaveBeenCalled()
+      expect(fetchMock).not.toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should prefer custom filename over extracted filename', () => {
+      const testUrl =
+        'https://example.com/api/file?filename=extracted-image.jpg'
+      const customFilename = 'custom-override.png'
+
+      downloadFile(testUrl, customFilename)
+
+      expect(mockLink.download).toBe(customFilename)
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should handle URLs with empty filename parameter', () => {
+      const testUrl = 'https://example.com/api/file?filename='
+
+      downloadFile(testUrl)
+
+      expect(mockLink.download).toBe('download.png')
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should handle relative URLs by using window.location.origin', () => {
+      const relativeUrl = '/api/file?filename=relative-image.png'
+
+      downloadFile(relativeUrl)
+
+      expect(mockLink.href).toBe(relativeUrl)
+      expect(mockLink.download).toBe('relative-image.png')
+      expect(fetchMock).not.toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('should clean up DOM elements after download', () => {
+      const testUrl = 'https://example.com/image.png'
+
+      downloadFile(testUrl)
+
+      // Verify the element was added and then removed
+      expect(document.body.appendChild).toHaveBeenCalledWith(mockLink)
+      expect(document.body.removeChild).toHaveBeenCalledWith(mockLink)
+      expect(fetchMock).not.toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+    })
+
+    it('streams downloads via blob when running in cloud', async () => {
+      mockIsCloud = true
+      const testUrl = 'https://storage.googleapis.com/bucket/file.bin'
+      const blob = new Blob(['test'])
+      const blobFn = vi.fn().mockResolvedValue(blob)
+      fetchMock.mockResolvedValue({
+        ok: true,
+        status: 200,
+        blob: blobFn
+      } as unknown as Response)
+
+      downloadFile(testUrl)
+
+      expect(fetchMock).toHaveBeenCalledWith(testUrl)
+      const fetchPromise = fetchMock.mock.results[0].value as Promise<Response>
+      await fetchPromise
+      const blobPromise = blobFn.mock.results[0].value as Promise<Blob>
+      await blobPromise
+      await Promise.resolve()
+      expect(blobFn).toHaveBeenCalled()
+      expect(createObjectURLSpy).toHaveBeenCalledWith(blob)
+      expect(revokeObjectURLSpy).toHaveBeenCalledWith('blob:mock-url')
+      expect(mockLink.click).toHaveBeenCalled()
+    })
+
+    it('logs an error when cloud fetch fails', async () => {
+      mockIsCloud = true
+      const testUrl = 'https://storage.googleapis.com/bucket/missing.bin'
+      const consoleSpy = vi.spyOn(console, 'error').mockImplementation(() => {})
+      fetchMock.mockResolvedValue({
+        ok: false,
+        status: 404,
+        blob: vi.fn()
+      } as unknown as Response)
+
+      downloadFile(testUrl)
+
+      expect(fetchMock).toHaveBeenCalledWith(testUrl)
+      const fetchPromise = fetchMock.mock.results[0].value as Promise<Response>
+      await fetchPromise
+      await Promise.resolve()
+      expect(consoleSpy).toHaveBeenCalled()
+      expect(createObjectURLSpy).not.toHaveBeenCalled()
+      consoleSpy.mockRestore()
+    })
+  })
+})

src/base/credits/comfyCredits.test.ts

@@ -0,0 +1,46 @@
+import { describe, expect, test } from 'vitest'
+
+import {
+  CREDITS_PER_USD,
+  COMFY_CREDIT_RATE_CENTS,
+  centsToCredits,
+  creditsToCents,
+  creditsToUsd,
+  formatCredits,
+  formatCreditsFromCents,
+  formatCreditsFromUsd,
+  formatUsd,
+  formatUsdFromCents,
+  usdToCents,
+  usdToCredits
+} from '@/base/credits/comfyCredits'
+
+describe('comfyCredits helpers', () => {
+  test('exposes the fixed conversion rate', () => {
+    expect(CREDITS_PER_USD).toBe(211)
+    expect(COMFY_CREDIT_RATE_CENTS).toBeCloseTo(2.11) // credits per cent
+  })
+
+  test('converts between USD and cents', () => {
+    expect(usdToCents(1.23)).toBe(123)
+    expect(formatUsdFromCents({ cents: 123, locale: 'en-US' })).toBe('1.23')
+  })
+
+  test('converts cents to credits and back', () => {
+    expect(centsToCredits(100)).toBe(211) // 100 cents = 211 credits
+    expect(creditsToCents(211)).toBe(100) // 211 credits = 100 cents
+  })
+
+  test('converts USD to credits and back', () => {
+    expect(usdToCredits(1)).toBe(211) // 1 USD = 211 credits
+    expect(creditsToUsd(211)).toBe(1) // 211 credits = 1 USD
+  })
+
+  test('formats credits and USD values using en-US locale', () => {
+    const locale = 'en-US'
+    expect(formatCredits({ value: 1234.567, locale })).toBe('1,234.57')
+    expect(formatCreditsFromCents({ cents: 100, locale })).toBe('211.00')
+    expect(formatCreditsFromUsd({ usd: 1, locale })).toBe('211.00')
+    expect(formatUsd({ value: 4.2, locale })).toBe('4.20')
+  })
+})