"Source on Save" checkbox disappears when a commented out testthat unit test exists in the script

[danwiththeplan]

System details

RStudio Edition : Desktop
RStudio Version : 2023.06.1+524 (2023.06.1+524)
OS Version      : MacOS 13.4.1 (c) (22F770820d)
R Version       :  4.2.0 (2022-04-22)

Steps to reproduce the problem

1. Open a new R script (File > Open File)
2. Check "Source on Save" checkbox
3. Save empty file ("Source on Save" checkbox remains)
4. Add to script:

library(testthat)
# test_that("an empty test", {
# })

5. Save file ("Source on Save" checkbox disappears)

Describe the problem in detail

"Source on Save" checkbox disappears when any unit test (even if commented out) exists in the script and the script is saved.

Describe the behavior you expected

"Source on Save" checkbox remains when any unit test (even if commented out) exists in the script and the script is saved.

• [ *] I have read the guide for submitting good bug reports.
• [* ] I have installed the latest version of RStudio, and confirmed that the issue still persists.
• [ *] If I am reporting an RStudio crash, I have included a diagnostics report.
• [* ] I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.