docs: add attribution comments to testing utilities

Author: mfazekas

example/src/testing/State.ts

@@ -1,3 +1,7 @@
+/**
+ * Chainable assertion API adapted from Nitro.
+ * @see https://github.com/mrousavy/nitro/blob/main/example/src/testing/State.ts
+ */
 import type { AssertionBackend, JSType } from './types';
 
 function stringify(value: unknown): string {

example/src/testing/createTestRunner.ts

@@ -1,3 +1,7 @@
+/**
+ * Test runner factory with timeout handling, adapted from Nitro.
+ * @see https://github.com/mrousavy/nitro/blob/main/example/src/testing/createTestRunner.ts
+ */
 import { State } from './State';
 import type { AssertionBackend } from './types';
 

example/src/testing/throwingBackend.ts

@@ -1,3 +1,7 @@
+/**
+ * Assertion backend that throws on failure, for in-app test UI.
+ * @see https://github.com/mrousavy/nitro/blob/main/example/src/testing/backends/throwing.ts
+ */
 import deepEqual from 'deep-equal';
 import type { AssertionBackend, JSType } from './types';
 

example/src/testing/types.ts

@@ -1,3 +1,7 @@
+/**
+ * Testing infrastructure adapted from Nitro's example app.
+ * @see https://github.com/mrousavy/nitro/tree/main/example/src/testing
+ */
 import type { RiveFile } from '@rive-app/react-native';
 
 export type JSType =