API returns true instead of NULL for last_modified_at fields

[zzgvh]

The organisation and project resources last_modified_at fields are not populated for all objects, so some of them have a NULL value. However the API returns those fields as boolean true which is clearly incorrect in a very surprising way.

Examples: http://rsr.akvo.org/api/v1/project/1880/?format=json and http://rsr.akvo.org/api/v1/organisation/1880/?format=xml

This is not an issue with project updates since they all have a populated last_modified_at, but a fix should be checked to work for project updates too.

[adriancollier]

I think we need to run a script to populate the created and modified dates for all projects and organisations in the DB.

We may still need to resolve this issue in the API as well - as I agree this is not expected behaviour, but all newly created objects should also already have these fields populated right?

[KasperBrandt]

I've now updated the API to show null instead of True. For populating the fields we need to set some sort of default, since we don't know when these projects / organisations have been created.

[KasperBrandt]

Merged in #623

[KasperBrandt]

Test plan

GIVEN the API for organisation, project and project updates
WHEN the created_at or last_modified_at datefields are empty
THEN the API should return 'null' instead of 'True'

[rumca]

I've tested with:

http://rsr.akvouat.org/api/v1/organisation/?format=json&limit=200
http://rsr.akvouat.org/api/v1/project/?format=json&limit=200&partnerships__organisation=420

both of which populate created_at and last_modified_at with null instead of true

The project updates API call doesn't return either of these fields