Salesforce Test.loadData without inserting the records?

Question

So, we have a Test Data Factory that creates many test Lead records. Some tests need inserted Leads with Ids, some do not.

I'm writing my Test Data Factory to reference a CSV file in Static Resources named 'testLeads'. The problem is that Test.loadData(lead.sObjectType, 'testLeads'); will insert the records before returning it.

What I have:

List<Lead> testLeads = Test.loadData(lead.sObjectType, 'testLeads');
Assert.isNotNull(testLeads[0].Id);

What I need:

List<Lead> testLeads = Test.loadData(lead.sObjectType, 'testLeads');
Assert.isNull(testLeads[0].Id);
insert testLeads;
Assert.isNotNull(testLeads[0].Id);