Add tests for ReconciliationText save

[AgustinSilverfin]

Description

A first attempt to start adding test coverage to the CLI. As discussed, starting with 'core' functionality, in this case ReconciliationText.save() method.

Type of change

• [ ] Bug fix
• [x] New feature
• [ ] Breaking change

Checklist

• [ ] README updated (if needed)
• [ ] Version updated (if needed)
• [ ] Documentation updated (if needed)