[trivial][bugfix] add include guard

[Yurlungur]

PR Summary

In PR #330 I missed an include guard in the new tests. Here the guard is added. Resolves #405 .

PR Checklist

• Adds a test for any bugs fixed. Adds tests for new features.
• Format your changes by using the make format command after configuring with cmake.
• Document any new features, update documentation for changes made.
• Make sure the copyright notice on any files you modified is up to date.
• After creating a pull request, note it in the CHANGELOG.md file.
• LANL employees: make sure tests pass both on the github CI and on the Darwin CI

If preparing for a new release, in addition please check the following:

• Update the version in cmake.
• Move the changes in the CHANGELOG.md file under a new header for the new release, and reset the categories.
• Ensure that any when='@main' dependencies are updated to the release version in the package.py

[jhp-lanl]

Looks good!

[jhp-lanl]

As a note for the future (or an additional one line change to add to this MR) would we maybe want to consider removing the spiner build from the minimal tests on github?

singularity-eos/.github/workflows/tests_minimal.yml

Line 31 in 09cf65c

-DSINGULARITY_USE_SPINER=ON \

[Yurlungur]

As a note for the future (or an additional one line change to add to this MR) would we maybe want to consider removing the spiner build from the minimal tests on github?

singularity-eos/.github/workflows/tests_minimal.yml

Line 31 in 09cf65c

-DSINGULARITY_USE_SPINER=ON \

Good suggestion. 👍 Done.