Add test for newlines at single line variables using pipe blocks

[ssbarnea]

Summary

vars:
  capture_file: |
    {{ something }}

I encountered accidental introduction of bugs while trying to shorten the line width or removal of the quoting and forget that | introduces a newline at the end. In some cases this newline breaks code.

The proposal is to add a test that warns user about dangers that this construct produces a string ending with a newline.

The warning should not appear if the code already has more than one line and should also be easy to bypass using a # noqa XYZ comment.

Issue Type

• Feature Idea

Additional Information

Here is example of change fixing such a bug https://review.opendev.org/#/c/722336/