My Apex Trigger works properly, but I'm having trouble with my test. Below is by test method:

@isTest
private class taskUpdateLeadStatusTests {

static testMethod void validateUpdateLeadStatusWithCall() {

Lead l = new Lead (LastName='Phillips', Company='Phil Inc.');
l.Status = 'Open';
insert l;

Task t = new Task();
t.Subject = 'Call';
t.Status = 'Completed';
t.WhoId = l.Id;
insert t;

System.assertEquals(l.Status, 'Contacted');

}

static testMethod void validateUpdateLeadStatusWithEmail() {

Lead l = new Lead (LastName='Phillips', Company='Phil Inc.');
l.Status = 'Open';
insert l;

Task t = new Task();
t.Subject = 'Email';
t.Status = 'Completed';
t.WhoId = l.Id;
insert t;

System.assertEquals(l.Status, 'Contacted');

}

}

Here is the trigger associated with the test:

trigger taskUpdateLeadStatus on Task (after insert, after update) {

list<lead> liLeads = new list<lead>();
list<id> liIds = new list<id>();

for(Task sTask : trigger.new)
{
if(sTask.Status == 'Completed' && (sTask.Subject == 'Call' || sTask.Subject == 'Email'))
{
liIds.add(sTask.WhoId);
}
}

for(Lead sLead : [select Id, Status from Lead where Id in : liIds])
{
sLead.Status = 'Contacted';
liLeads.add(sLead);
}

update liLeads;

}

Can someone provide guidance on this topic? 

Thanks,