Add unit tests for otsUtils and coverage evaluation report

[UozumiMizuto]

Motivation

• Improve test coverage for otsUtils utilities and document current coverage state for protocol and utils.
• Surface untested branches (filesystem recursion, stamping/upgrading flows, and OpenTimestamps interaction) so they can be targeted by future tests.

Description

• Add COVERAGE_EVALUATION.md summarizing scope checked, well-covered areas, uncovered behaviors, tooling status, and recommended next tests.
• Add src/otsUtils.test.ts which provides a mocked in-memory filesystem and mocked window.OpenTimestamps to unit-test otsUtil behaviors.
• Implement tests for getAllFilesRecursive filtering, generateRepoHash protocol equivalence, upgradeAll behaviors for missing and stale entries (rewrites .ots and clears pending registry), and stampHash / getInfo delegation to OpenTimestamps.
• Use vitest test helpers and spies (vi) to assert interactions and side effects.

Testing

• Ran the new unit tests with Vitest and the src/otsUtils.test.ts suite; tests completed and asserted expected behavior for all covered cases.
• Attempted a coverage run with npx vitest run --config vitest.config.ts --coverage, but it failed due to a missing provider dependency: @vitest/coverage-v8 which prevented line/branch coverage output.
• No other automated test failures were observed in the added test file execution.

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Codex Task

[gemini-code-assist]

Code Review

This pull request introduces a test coverage evaluation document and a new unit test suite for otsUtils.ts. The tests utilize a custom mock filesystem to verify file recursion, repository hashing, and OpenTimestamps integration. Review feedback suggests enhancing test isolation by clearing global state in afterEach, expanding test coverage for time-based upgrade logic, and adopting Vitest's fake timers to manage internal timeouts.

[gemini-code-assist]

The tests modify the global window.OpenTimestamps object. To prevent side effects and ensure test isolation, you should reset this property after each test.

Suggested change

	beforeEach(() => {
	vi.restoreAllMocks();
	});
	afterEach(() => {
	vi.restoreAllMocks();
	delete (window as any).OpenTimestamps;
	});

[gemini-code-assist]

The current test for upgradeAll uses a null value for the last attempt, which only covers the !lastAttempt branch. To fully verify the logic in otsUtils.ts, you should also include test cases for the 2-hour threshold (e.g., one entry that is too fresh to upgrade and one that is old enough).

[gemini-code-assist]

The upgradeAll function in otsUtils.ts uses a setTimeout for a 30-second timeout during the upgrade process. In a testing environment, this can lead to hanging processes or flaky tests if the timer is not managed. It is recommended to use Vitest's fake timers to control time-dependent logic.

Suggested change

	import { beforeEach, describe, expect, it, vi } from 'vitest';
	import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';