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>

tests-ui/tests/renderer/extensions/vueNodes/widgets/components/WidgetSelectDropdown.test.ts

@@ -1,174 +0,0 @@
-import { createTestingPinia } from '@pinia/testing'
-import { mount } from '@vue/test-utils'
-import type { VueWrapper } from '@vue/test-utils'
-import PrimeVue from 'primevue/config'
-import type { ComponentPublicInstance } from 'vue'
-import { describe, expect, it, vi } from 'vitest'
-
-import type { ComboInputSpec } from '@/schemas/nodeDef/nodeDefSchemaV2'
-import type { DropdownItem } from '@/renderer/extensions/vueNodes/widgets/components/form/dropdown/types'
-import type { SimplifiedWidget } from '@/types/simplifiedWidget'
-
-import WidgetSelectDropdown from '@/renderer/extensions/vueNodes/widgets/components/WidgetSelectDropdown.vue'
-
-interface WidgetSelectDropdownInstance extends ComponentPublicInstance {
-  inputItems: DropdownItem[]
-  outputItems: DropdownItem[]
-  updateSelectedItems: (selectedSet: Set<string>) => void
-}
-
-describe('WidgetSelectDropdown custom label mapping', () => {
-  const createMockWidget = (
-    value: string = 'img_001.png',
-    options: {
-      values?: string[]
-      getOptionLabel?: (value: string | null) => string
-    } = {},
-    spec?: ComboInputSpec
-  ): SimplifiedWidget<string | undefined> => ({
-    name: 'test_image_select',
-    type: 'combo',
-    value,
-    options: {
-      values: ['img_001.png', 'photo_abc.jpg', 'hash789.png'],
-      ...options
-    },
-    spec
-  })
-
-  const mountComponent = (
-    widget: SimplifiedWidget<string | undefined>,
-    modelValue: string | undefined,
-    assetKind: 'image' | 'video' | 'audio' = 'image'
-  ): VueWrapper<WidgetSelectDropdownInstance> => {
-    return mount(WidgetSelectDropdown, {
-      props: {
-        widget,
-        modelValue,
-        assetKind,
-        allowUpload: true,
-        uploadFolder: 'input'
-      },
-      global: {
-        plugins: [PrimeVue, createTestingPinia()]
-      }
-    }) as unknown as VueWrapper<WidgetSelectDropdownInstance>
-  }
-
-  describe('when custom labels are not provided', () => {
-    it('uses values as labels when no mapping provided', () => {
-      const widget = createMockWidget('img_001.png')
-      const wrapper = mountComponent(widget, 'img_001.png')
-
-      const inputItems = wrapper.vm.inputItems
-      expect(inputItems).toHaveLength(3)
-      expect(inputItems[0].name).toBe('img_001.png')
-      expect(inputItems[0].label).toBe('img_001.png')
-      expect(inputItems[1].name).toBe('photo_abc.jpg')
-      expect(inputItems[1].label).toBe('photo_abc.jpg')
-      expect(inputItems[2].name).toBe('hash789.png')
-      expect(inputItems[2].label).toBe('hash789.png')
-    })
-  })
-
-  describe('when custom labels are provided via getOptionLabel', () => {
-    it('displays custom labels while preserving original values', () => {
-      const getOptionLabel = vi.fn((value: string | null) => {
-        if (!value) return 'No file'
-        const mapping: Record<string, string> = {
-          'img_001.png': 'Vacation Photo',
-          'photo_abc.jpg': 'Family Portrait',
-          'hash789.png': 'Sunset Beach'
-        }
-        return mapping[value] || value
-      })
-
-      const widget = createMockWidget('img_001.png', {
-        getOptionLabel
-      })
-      const wrapper = mountComponent(widget, 'img_001.png')
-
-      const inputItems = wrapper.vm.inputItems
-      expect(inputItems).toHaveLength(3)
-      expect(inputItems[0].name).toBe('img_001.png')
-      expect(inputItems[0].label).toBe('Vacation Photo')
-      expect(inputItems[1].name).toBe('photo_abc.jpg')
-      expect(inputItems[1].label).toBe('Family Portrait')
-      expect(inputItems[2].name).toBe('hash789.png')
-      expect(inputItems[2].label).toBe('Sunset Beach')
-
-      expect(getOptionLabel).toHaveBeenCalledWith('img_001.png')
-      expect(getOptionLabel).toHaveBeenCalledWith('photo_abc.jpg')
-      expect(getOptionLabel).toHaveBeenCalledWith('hash789.png')
-    })
-
-    it('emits original values when items with custom labels are selected', async () => {
-      const getOptionLabel = vi.fn((value: string | null) => {
-        if (!value) return 'No file'
-        return `Custom: ${value}`
-      })
-
-      const widget = createMockWidget('img_001.png', {
-        getOptionLabel
-      })
-      const wrapper = mountComponent(widget, 'img_001.png')
-
-      // Simulate selecting an item
-      const selectedSet = new Set(['input-1']) // index 1 = photo_abc.jpg
-      wrapper.vm.updateSelectedItems(selectedSet)
-
-      // Should emit the original value, not the custom label
-      expect(wrapper.emitted('update:modelValue')).toBeDefined()
-      expect(wrapper.emitted('update:modelValue')![0]).toEqual([
-        'photo_abc.jpg'
-      ])
-    })
-
-    it('falls back to original value when label mapping fails', () => {
-      const getOptionLabel = vi.fn((value: string | null) => {
-        if (value === 'photo_abc.jpg') {
-          throw new Error('Mapping failed')
-        }
-        return `Labeled: ${value}`
-      })
-
-      const consoleErrorSpy = vi
-        .spyOn(console, 'error')
-        .mockImplementation(() => {})
-
-      const widget = createMockWidget('img_001.png', {
-        getOptionLabel
-      })
-      const wrapper = mountComponent(widget, 'img_001.png')
-
-      const inputItems = wrapper.vm.inputItems
-      expect(inputItems[0].name).toBe('img_001.png')
-      expect(inputItems[0].label).toBe('Labeled: img_001.png')
-      expect(inputItems[1].name).toBe('photo_abc.jpg')
-      expect(inputItems[1].label).toBe('photo_abc.jpg')
-      expect(inputItems[2].name).toBe('hash789.png')
-      expect(inputItems[2].label).toBe('Labeled: hash789.png')
-
-      expect(consoleErrorSpy).toHaveBeenCalled()
-      consoleErrorSpy.mockRestore()
-    })
-  })
-
-  describe('output items with custom label mapping', () => {
-    it('applies custom label mapping to output items from queue history', () => {
-      const getOptionLabel = vi.fn((value: string | null) => {
-        if (!value) return 'No file'
-        return `Output: ${value}`
-      })
-
-      const widget = createMockWidget('img_001.png', {
-        getOptionLabel
-      })
-      const wrapper = mountComponent(widget, 'img_001.png')
-
-      const outputItems = wrapper.vm.outputItems
-      expect(outputItems).toBeDefined()
-      expect(Array.isArray(outputItems)).toBe(true)
-    })
-  })
-})