test: fixed multipartStart.test.ts

[egordidenko]

Description

Checklist

• Tests (if applicable)
• Documentation (if applicable)
• Changelog stub (or use conventional commit messages)

[Copilot]

Pull Request Overview

This PR re-enables the previously skipped multipartStart test suite by removing the .skip modifier and updates the error assertion for the "should be rejected with bad options" test case to use a regex pattern instead of an exact error message match.

• Re-enabled the multipartStart test suite
• Modified error assertion to use regex pattern matching
• Split error type and message verification into two separate assertions

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The assertion pattern used here is inconsistent with the rest of the test file. At line 33-35, a similar test uses toThrowError(new UploadError(...)) to assert both the error type and message in a single assertion. Consider using the same pattern for consistency:

await expect(upload).rejects.toThrowError(
  new UploadError(
    'File size can not be less than 10485760 bytes. Please use direct upload instead of multipart.'
  )
)

Alternatively, if the exact error message is dynamic (e.g., the byte count changes), the current approach with a regex is reasonable, but then the pattern should be applied consistently across all similar tests in this file.

Suggested change

	await expect(upload).rejects.toThrow(UploadError)
	await expect(upload).rejects.toThrow(
	/File size can not be less than \d+ bytes\. Please use direct upload instead of multipart\./
	await expect(upload).rejects.toThrowError(
	new UploadError(
	'File size can not be less than 10485760 bytes. Please use direct upload instead of multipart.'
	)