Implement storage nfs-on-slave test

This new test ensures that the "nfs-on-slave" host-plugin does
check something, and return different result based on the environment.

Signed-off-by: Anthony PERARD <[email protected]>

Author: tperard

tests/storage/nfs/test_nfs_sr.py

@@ -1,8 +1,15 @@
 import pytest
 
+from lib.commands import SSHCommandFailed
 from lib.common import vm_image, wait_for
+from lib.vdi import VDI
 from tests.storage import vdi_is_open
 
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from lib.vm import VM
+
 # Requirements:
 # - one XCP-ng host >= 8.0 with an additional unused disk for the SR
 
@@ -30,6 +37,39 @@ def test_vdi_is_not_open(self, dispatch_nfs):
         vdi = dispatch_nfs
         assert not vdi_is_open(vdi)
 
+    @pytest.mark.small_vm
+    @pytest.mark.usefixtures('hostA2')
+    def test_plugin_nfs_on_on_slave(self, vm_on_nfs_sr: 'VM'):
+        vm = vm_on_nfs_sr
+        vm.start()
+        vm.wait_for_os_booted()
+        host = vm.get_residence_host()
+
+        vdi = VDI(vm.vdi_uuids()[0], host=host)
+        image_format = vdi.get_image_format()
+        if not image_format:
+            image_format = "vhd"
+
+        vdi_path = f"/run/sr-mount/{vdi.sr.uuid}/{vdi.uuid}.{image_format}"
+
+        # nfs-on-slave returns an error when the VDI is open on the host.
+        # Otherwise, it return "success", including in case "path" doesn't exist
+        with pytest.raises(SSHCommandFailed) as excinfo:
+            assert vm.is_running_on_host(host)
+            host.call_plugin("nfs-on-slave", "check", {"path": vdi_path})
+
+        # The output of the host plugin would have "stdout: NfsCheckException"
+        # and information about which process has the path open.
+        assert "NfsCheckException" in excinfo.value.stdout
+
+        for member in host.pool.hosts:
+            # skip the host where the VM is running
+            if member.uuid == host.uuid:
+                continue
+            member.call_plugin("nfs-on-slave", "check", {"path": vdi_path})
+
+        vm.shutdown(verify=True)
+
     @pytest.mark.small_vm # run with a small VM to test the features
     @pytest.mark.big_vm # and ideally with a big VM to test it scales
     # Make sure this fixture is called before the parametrized one