Cannot use file($settings::localcacert) in my manifest, tests fail

[threepistons]

Describe the Bug

When I try to write tests for a manifest to replace the CA cert across my nodes, very like this one.
I get

1) profiles::replace_ca_cert All tests is expected to compile into a catalogue without dependency cycles
     Failure/Error: it { is_expected.to compile.with_all_deps }
       error during compilation: Evaluation Error: Error while evaluating a Function Call, Could not find any files from /dev/null/ssl/certs/ca.pem (file: /home/ucs/102/redacted/git/computing_linux_puppet_controlrepo/site/profiles/spec/fixtures/modules/profiles/manifests/replace_ca_cert.pp, line: 16, column: 16) on node redacted.uni.ac.uk

  7) profiles::replace_ca_cert All tests is expected to contain File[/etc/puppetlabs/puppet/ssl/certs/ca.pem] with ensure => "file" and replace => "yes"
     Failure/Error:
       is_expected.to contain_file('/etc/puppetlabs/puppet/ssl/certs/ca.pem').with(
         'ensure'  => 'file',
         'replace' => 'yes',
       )

     Puppet::PreformattedError:
       Evaluation Error: Error while evaluating a Function Call, Could not find any files from /dev/null/ssl/certs/ca.pem (file: /home/ucs/102/redacted/git/computing_linux_puppet_controlrepo/site/profiles/spec/fixtures/modules/profiles/manifests/replace_ca_cert.pp, line: 16, column: 16) on node redacted.uni.ac.uk

and further identical errors for each OS under test.

Expected Behaviour

I expected the manifest to compile.

Steps to Reproduce

Steps to reproduce the behaviour:

1. pdk new class replace_ca_cert in my profiles module.
2. Paste replace_ca_cert.pp.txt into manifests/replace_ca_cert.pp.
3. Paste replace_ca_cert_spec.rb.txt into spec/classes/replace_ca_cert_spec.rb.
4. pdk validate ; pdk test unit

Environment

• PDK 2.6.1 (I don't get to update this, I don't have root on the timeshare I'm using).
• Control repo with roles and profiles. The rest of the control repo passes unit tests.
• CentOS Linux release 7.9.2009 (Core)

Additional Context

Replacing the file resource's content with a string instead of file($settings::localcacert) in replace_ca_cert.pp compiled perfectly, but that's not the behaviour I need.

I'm hoping that the answer turns out to be something really simple like "put X line into Y file". Google, Stack Exchange, etc revealed nothing of the sort.

[threepistons]

I get the same result with PDK 3.0.0 on a different system.

[mmarseglia]

Hi @threepistons did you ever find a solution? I have the same issue.