We use the `notify_credentials` management command to keep certificate- related data in the LMS and Credentials service in sync. We can run it with specific arguments (user_ids, course_keys, etc.) when we notice a data discrepancy; and it is run regularly by a Jenkins job with the `--auto` flag every ~4 hours to keep things up-to-date. Because we probably never want to notify credentials of of ALL the GeneratedCertificates, the celery task must be given some arguments to filter down to the relevant certificates. Running the management command with the `--auto` flag (as the Jenkins job does) adds `start_date` and `end_date` arguments of 4 hours ago and now, respectively. The handle_notify_credentials celery task then takes those arguments and looks for any GeneratedCertificates that have been modified within the given time range by checking the GeneratedCertificate modified_date. It will send the current data for those certificates to credentials. However, we also want to notify credentials about certificates that have an associated CertificateDateOverride that has changed within that time range: added, updated, or deleted. But changes to a CertificateDateOverride won’t affect the GeneratedCertificate’s modified date, and therefore wouldn’t be included in the list of certs cent to credentials. This commit adds a check for changed CertificateDateOverrides and includes their associated GeneratedCertificates in the list of certs. We use the CertificateDateOverride’s history model for this check so that we can include certificates whose override was deleted. MICROBA-1489
LMS (Learning Management System) -------------------------------- This directory contains code relating to the student portal for edX.