👷 Tests are failing in Singularity on GitHub Actions but passing locally

[shnizzedy]

Describe the bug

1. Tests succeed with pytest --doctest-modules --platform singularity locally
2. Tests fail with pytest --doctest-modules --platform singularity on GitHub Actions
   1. without --cleanenv:

      FATAL:   While making image from oci registry: error fetching image to cache: while building SIF from layers: unable to create new build: failed to find mount point for $GITHUB_WORKSPACE/.singularity/tmp: no parent mount point found

   2. with --cleanenv:

      FATAL:   Couldn't not parse configuration file /opt/hostedtoolcache/singularity/3.7.1/x64/etc/singularity/singularity.conf: open /opt/hostedtoolcache/singularity/3.7.1/x64/etc/singularity/singularity.conf: no such file or directory

To reproduce

In a branch or fork, add singluarity back to https://github.com/FCP-INDI/cpac/blob/0b166d597ac2efedd36bf5777b472122e1b2b781/.github/workflows/test_cpac.yml#L22 and push to GitHub

Expected behavior

Singularity image builds and runs on GitHub Actions

Acceptance criteria

• [ ] Singularity tests that pass locally also pass on GitHub Actions

Screenshots

No response

C-PAC version

v1.8.3

Container platform

Singularity

Docker and/or Singularity version(s)

3.6.4, 3.7, 3.8

Additional context

No response