@Test (priority=100)
public void clearCart()
{

   try
   {
      pcs.clearCart("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa1000");
      Assert.fail("System remove cart of an unknown user ?");
   }
   catch (Exception e)
   {
      // Shall raise an exception because user is unknown.
   }
   
   try
   {
      pcs.clearCart("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa3");
   }
   catch (Exception e)
   {
      Assert.fail("Cannot remove single cart of existing user.", e);
   }
   
   try
   {
      pcs.clearCart("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa1");
   }
   catch (Exception e)
   {
      Assert.fail("Cannot remove empty cart of existing user.", e);
   }
   try
   {
      pcs.clearCart("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa2");
   }
   catch (Exception e)
   {
      Assert.fail("Cannot remove multi-cart of existing user.", e);
   }
}