docs: move LiteGraph test guidance into docs

Move the litegraph-specific CodeRabbit review rules into docs/testing/litegraph-testing.md, link the guide from docs/testing/README.md, and keep .coderabbit.yaml as a path-to-docs bridge.

Verification: parsed .coderabbit.yaml with Ruby YAML and ran git diff --check.

Author: huang47

.coderabbit.yaml

@@ -70,12 +70,7 @@ reviews:
         Treat `.agents/checks/test-quality.md`, `docs/testing/README.md`, and `docs/guidance/vitest.md` as required review context for every changed Vitest test file.
     - path: 'src/lib/litegraph/**/*.test.ts'
       instructions: |
-        Treat `.agents/checks/test-quality.md`, `docs/testing/README.md`, and `docs/guidance/vitest.md` as required review context for every changed litegraph Vitest test file.
-        Reuse shared factories in `src/utils/__tests__/litegraphTestUtils.ts` instead of hand-rolling litegraph node, canvas, graph, subgraph, or workflow builders.
-        Flag mocked litegraph classes when a real instance or shared factory would exercise behavior directly.
-        When a PR changes litegraph graph deserialization, link loading, nullable serialized links, or sparse legacy link handling, require direct regression coverage for the changed runtime path. Helper-only coverage in a different utility is insufficient.
-        For `LGraph.configure()` sparse legacy links, expect a test that constructs an `LGraph`, calls `configure()` with a v0.4 payload containing `links: [null, validLink]`, asserts it does not throw, and asserts the valid link is still created.
-        For link-retargeting or widget-slot compression changes such as `compressWidgetInputSlots()`, expect a direct test of the compression path with `links: [null, validLink]` that proves the valid link is still retargeted while the null entry is ignored.
+        Treat `.agents/checks/test-quality.md`, `docs/testing/README.md`, `docs/guidance/vitest.md`, and `docs/testing/litegraph-testing.md` as required review context for every changed litegraph Vitest test file.
     - path: '{browser_tests,apps/website/e2e}/**/*.spec.ts'
       instructions: |
         Treat `.agents/checks/test-quality.md`, `docs/testing/README.md`, and `docs/guidance/playwright.md` as required review context for every changed Playwright test file.

docs/testing/README.md

@@ -4,11 +4,12 @@ This guide provides an overview of testing approaches used in the ComfyUI Fronte
 
 ## Testing Documentation
 
-Documentation for unit tests is organized into three guides:
+Documentation for unit tests is organized into four guides:
 
 - [Component Testing](./component-testing.md) - How to test Vue components
 - [Unit Testing](./unit-testing.md) - How to test utility functions, composables, and other non-component code
 - [Store Testing](./store-testing.md) - How to test Pinia stores specifically
+- [LiteGraph Testing](./litegraph-testing.md) - How to test LiteGraph graph, node, link, and workflow behavior
 
 ## Testing Structure
 

docs/testing/litegraph-testing.md

@@ -0,0 +1,17 @@
+# LiteGraph Testing Guide
+
+This guide covers test patterns for LiteGraph graph, node, link, subgraph, and workflow behavior in ComfyUI Frontend.
+
+## Shared Factories
+
+Reuse shared factories in `src/utils/__tests__/litegraphTestUtils.ts` instead of hand-rolling LiteGraph node, canvas, graph, subgraph, or workflow builders.
+
+Use real LiteGraph instances or shared factories when they exercise behavior directly. Avoid mocking LiteGraph classes unless the test is intentionally checking a seam outside LiteGraph itself.
+
+## Runtime Path Coverage
+
+When a PR changes LiteGraph graph deserialization, link loading, nullable serialized links, or sparse legacy link handling, add direct regression coverage for the changed runtime path. Helper-only coverage in a different utility is not enough when the changed branch is reached through the runtime path.
+
+For `LGraph.configure()` sparse legacy links, construct an `LGraph`, call `configure()` with a v0.4 payload containing `links: [null, validLink]`, assert that it does not throw, and assert that the valid link is still created.
+
+For link retargeting or widget-slot compression changes such as `compressWidgetInputSlots()`, test the compression path directly with `links: [null, validLink]`. The test should prove that the valid link is still retargeted while the null entry is ignored.