I'm doing following:

def default_get(self, cr, uid, fields, context=None):
    data = super(extended_projects, self).default_get(cr, uid, fields, context=context)
    data['test_field'] = context.get('test_field','default_value')
    return data

This works and sets the default values.

But I need to set it dynamically, specifically in the fields_view_get method (which I'm overriding as well).

if I do this (in fields_view_get):

    context['test_field'] = 'new_default_value'
    test_data = self.default_get(cr, uid, ['test_field'], context=context)

The new default value doesn't show for the field.