[SPARK-47309] [XML] Add schema inference unit tests

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: SQL
• Labels: pull-request-available
• Assignee: Shujing Yang
• Reporter: Shujing Yang
• Created: 06/Mar/24 21:16
• Updated: 20/Mar/24 01:16
• Resolved: 08/Mar/24 00:44

Description

As titled.

It also fixes schema inference issue

1) when there's an empty tag

2) when merging schema for NullType

Issue Links

• links to: GitHub Pull Request #45411
• links to: GitHub Pull Request #45426
• links to: GitHub Pull Request #45538