tests: wait for /dev/ptp0 to appear

We have sometimes seen that this test can fail. In theory it could
happen that udev has not created the /dev/ptp0 file before we run the
ssh command.

So let's wait in udev for the device to appear up to 5 seconds.

Signed-off-by: Pablo Barbáchano <pablob@amazon.com>

Author: pb8o

tests/integration_tests/functional/test_kvm_ptp.py

@@ -6,19 +6,18 @@
 import pytest
 
 
-def test_kvm_ptp(uvm_plain_any):
+def test_kvm_ptp(uvm_any_booted):
     """Test kvm_ptp is usable"""
 
-    vm = uvm_plain_any
+    vm = uvm_any_booted
     if vm.guest_kernel_version[:2] < (6, 1):
         pytest.skip("Only supported in kernel 6.1 and after")
 
-    vm.spawn()
-    vm.basic_config(vcpu_count=2, mem_size_mib=256)
-    vm.add_net_iface()
-    vm.start()
+    _, dmesg, _ = vm.ssh.check_output("dmesg |grep -i ptp")
+    assert "PTP clock support registered" in dmesg
 
-    vm.ssh.check_output("[ -c /dev/ptp0 ]")
+    # wait up to 5s to see the PTP device
+    vm.ssh.check_output("udevadm wait -t 5 /dev/ptp0")
 
     # phc_ctl[14515.127]: clock time is 1697545854.728335694 or Tue Oct 17 12:30:54 2023
     vm.ssh.check_output("phc_ctl /dev/ptp0 -- get")