Some PX files are not included in the generated DCAT file

[mariusfranzen]

Issue
When I generate a DCAT file from PX files, some of the PX files are not included in the DCAT. There are no errors or messages.
We have discovered that this happened because the PX files that were not included in the DCAT, did not have the optional fields "SOURCE" and "LAST UPDATED". Optional files should be optional.

Note: SCB is aware of this problem as I've been in contact with them about this, but I figured it should be posted here so that people with the same issue can find this.

To Reproduce
Steps to reproduce the behavior:

1. Create a bunch of PX files, some of which does not have the fields "SOURCE" and "LAST UPDATED"
2. Use the admin interface of PxWeb to generate a DCAT using a database of the previously created PX files
3. Open the DCAT file
4. The PX files without the fields mentioned before are not included in the DCAT.

Expected behavior
All files should be included as long as all required fields are provided

Actual behavior
PxWeb ignores some files because some optional fields are missing.

[likp]

Thanks @mariusfranzen for finding this. Even if SOURCE and LAST-UPDATE are optional keywords in the PX-file they are actually mandatory for the generation of the DCAT-AP file. We will update the user instructions for this.