Arvados

Incorrect test cases in source:sdk/go/manifest/manifest_test.go that disagree with the documented Keep locator format:

• "A2345678901234abcdefababdeffdfdf+12345" is listed valid, but is invalid. The hash part is not allowed to contain uppercase letters.
• "12345678901234567890123456789012+12345+A" is listed invalid, but is valid. Hint content is allowed to be empty.

The regexp in manifest.go should match the one given on the wiki page, and test cases should be updated accordingly.

Asides:

• Sharing a single set of test cases among all SDKs' test suites might help prevent this bug from reappearing.
• In case that regexp ever changes, we could designate one SDK as the official regexp, and link the wiki page to the appropriate source file instead of trying to keep them synchronized manually.