Remove OpenStruct from the project (solve warnings)

[arthurhess]

Description of the change

This pull request aims to solve one of the warnings we've been getting when loading the gem (#1165)

/usr/local/lib/ruby/3.3.0/json/common.rb:3: warning: ostruct was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add ostruct to your Gemfile or gemspec to silence this warning.

OpenStruct was introduced in the project back in 2017 to be used a test double.

I'm proposing replacing those OpenStruct instances with RSpec doubles.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Maintenance
• New release

Related issues

Shortcut stories and GitHub issues (delete irrelevant)

• Fix Warning about logger and ostruct in Ruby v3.3.5 #1165

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers assigned
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer

[arthurhess]

@waltjones Ready for review, and happy to make any adjustments as needed. 🙏 Thank you!

[waltjones]

@arthurhess Thank you for the PR!