CLN: split #1928, refactor render test

[fangchenli]

Reference Issues or PRs

#1928

What does this implement/fix?

Put a x in the boxes that apply

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds a feature)
• [ ] Breaking change (fix or feature that would cause existing features not to work as expected)
• [ ] Documentation Update
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no API changes)
• [ ] Build related changes
• [ ] Other (please describe):

Testing

• [ ] Did you test the pull request locally?
• [ ] Did you add new tests?

Any other comments?