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/core/graph/subgraph/proxyWidget.test.ts

@@ -0,0 +1,121 @@
+import { describe, expect, test, vi } from 'vitest'
+
+import { registerProxyWidgets } from '@/core/graph/subgraph/proxyWidget'
+import { parseProxyWidgets } from '@/core/schemas/proxyWidget'
+import { LGraphNode } from '@/lib/litegraph/src/litegraph'
+import type { LGraphCanvas, SubgraphNode } from '@/lib/litegraph/src/litegraph'
+
+import {
+  createTestSubgraph,
+  createTestSubgraphNode
+} from '@/lib/litegraph/src/subgraph/__fixtures__/subgraphHelpers'
+
+const canvasEl: Partial<HTMLCanvasElement> = { addEventListener() {} }
+const canvas: Partial<LGraphCanvas> = { canvas: canvasEl as HTMLCanvasElement }
+registerProxyWidgets(canvas as LGraphCanvas)
+
+vi.mock('@/renderer/core/canvas/canvasStore', () => ({
+  useCanvasStore: () => ({})
+}))
+vi.mock('@/stores/domWidgetStore', () => ({
+  useDomWidgetStore: () => ({ widgetStates: new Map() })
+}))
+vi.mock('@/services/litegraphService', () => ({
+  useLitegraphService: () => ({ updatePreviews: () => ({}) })
+}))
+
+function setupSubgraph(
+  innerNodeCount: number = 0
+): [SubgraphNode, LGraphNode[]] {
+  const subgraph = createTestSubgraph()
+  const subgraphNode = createTestSubgraphNode(subgraph)
+  subgraphNode._internalConfigureAfterSlots()
+  const graph = subgraphNode.graph
+  graph.add(subgraphNode)
+  const innerNodes = []
+  for (let i = 0; i < innerNodeCount; i++) {
+    const innerNode = new LGraphNode(`InnerNode${i}`)
+    subgraph.add(innerNode)
+    innerNodes.push(innerNode)
+  }
+  return [subgraphNode, innerNodes]
+}
+
+describe('Subgraph proxyWidgets', () => {
+  test('Can add simple widget', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(1)
+    innerNodes[0].addWidget('text', 'stringWidget', 'value', () => {})
+    subgraphNode.properties.proxyWidgets = [['1', 'stringWidget']]
+    expect(subgraphNode.widgets.length).toBe(1)
+    expect(subgraphNode.properties.proxyWidgets).toStrictEqual([
+      ['1', 'stringWidget']
+    ])
+  })
+  test('Can add multiple widgets with same name', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(2)
+    for (const innerNode of innerNodes)
+      innerNode.addWidget('text', 'stringWidget', 'value', () => {})
+    subgraphNode.properties.proxyWidgets = [
+      ['1', 'stringWidget'],
+      ['2', 'stringWidget']
+    ]
+    expect(subgraphNode.widgets.length).toBe(2)
+    expect(subgraphNode.widgets[0].name).not.toEqual(
+      subgraphNode.widgets[1].name
+    )
+  })
+  test('Will serialize existing widgets', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(1)
+    innerNodes[0].addWidget('text', 'istringWidget', 'value', () => {})
+    subgraphNode.addWidget('text', 'stringWidget', 'value', () => {})
+
+    const proxyWidgets = parseProxyWidgets(subgraphNode.properties.proxyWidgets)
+    proxyWidgets.push(['1', 'istringWidget'])
+    subgraphNode.properties.proxyWidgets = proxyWidgets
+
+    expect(subgraphNode.widgets.length).toBe(2)
+    expect(subgraphNode.widgets[0].name).toBe('stringWidget')
+    subgraphNode.properties.proxyWidgets = [proxyWidgets[1], proxyWidgets[0]]
+    expect(subgraphNode.widgets[0].name).toBe('1: istringWidget')
+  })
+  test('Will mirror changes to value', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(1)
+    innerNodes[0].addWidget('text', 'stringWidget', 'value', () => {})
+    subgraphNode.properties.proxyWidgets = [['1', 'stringWidget']]
+    expect(subgraphNode.widgets.length).toBe(1)
+    expect(subgraphNode.widgets[0].value).toBe('value')
+    innerNodes[0].widgets![0].value = 'test'
+    expect(subgraphNode.widgets[0].value).toBe('test')
+    subgraphNode.widgets[0].value = 'test2'
+    expect(innerNodes[0].widgets![0].value).toBe('test2')
+  })
+  test('Will not modify position or sizing of existing widgets', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(1)
+    innerNodes[0].addWidget('text', 'stringWidget', 'value', () => {})
+    subgraphNode.properties.proxyWidgets = [['1', 'stringWidget']]
+    if (!innerNodes[0].widgets) throw new Error('node has no widgets')
+    innerNodes[0].widgets[0].y = 10
+    innerNodes[0].widgets[0].last_y = 11
+    innerNodes[0].widgets[0].computedHeight = 12
+    subgraphNode.widgets[0].y = 20
+    subgraphNode.widgets[0].last_y = 21
+    subgraphNode.widgets[0].computedHeight = 22
+    expect(innerNodes[0].widgets[0].y).toBe(10)
+    expect(innerNodes[0].widgets[0].last_y).toBe(11)
+    expect(innerNodes[0].widgets[0].computedHeight).toBe(12)
+  })
+  test('Can detach and re-attach widgets', () => {
+    const [subgraphNode, innerNodes] = setupSubgraph(1)
+    innerNodes[0].addWidget('text', 'stringWidget', 'value', () => {})
+    subgraphNode.properties.proxyWidgets = [['1', 'stringWidget']]
+    if (!innerNodes[0].widgets) throw new Error('node has no widgets')
+    expect(subgraphNode.widgets[0].value).toBe('value')
+    const poppedWidget = innerNodes[0].widgets.pop()
+    //simulate new draw frame
+    subgraphNode.widgets[0].computedHeight = 10
+    expect(subgraphNode.widgets[0].value).toBe(undefined)
+    innerNodes[0].widgets.push(poppedWidget!)
+    subgraphNode.widgets[0].computedHeight = 10
+    expect(subgraphNode.widgets[0].value).toBe('value')
+  })
+})