FSM Transitions conditions

In some cases there are additional requirements in order to allow the process to go to the next step. For this, custom conditions that integrates with transitions out of the box, were built.

Base classes for them:

• BaseTransitionCheck - base check which collects validation errors inside get_errors function and raise them if conditions are not met.

• BaseRequiredFieldsCheck - has fields attribute which contain list of required fields to allow performing of transition.

Examples:

Check that attachments of specific type are provided:

class ReportAttachmentsCheck(BaseTransitionCheck):
    def get_errors(self, instance, *args, **kwargs):
        errors = super().get_errors(*args, **kwargs)

        if not instance.report_attachments.filter(file_type__name='report').exists():
            errors['report_attachments'] = _('You should attach report.')
        return errors

Check that partner and all required focal points are provided before visit assignment:

class TPMVisitAssignRequiredFieldsCheck(BaseRequiredFieldsCheck):
    fields = [
        'tpm_partner', 'unicef_focal_points', 'tpm_partner_focal_points'
    ]

Example of the error response in case of unmet conditions: