KVM Test: Add new test qemu_guest_agent_snapshot

This test script runs live snapshot after guest
fs is frozen, then check if the file created on
guest disk is correct.
Signed-off-by: NQingtang Zhou <qzhou@redhat.com>

kvm/tests/qemu_guest_agent_snapshot.py

+import logging
+from autotest.client.shared import error
+from virttest import storage
+
+from qemu_guest_agent import QemuGuestAgentBasicCheck
+
+
+class QemuGuestAgentSnapshotTest(QemuGuestAgentBasicCheck):
+    @error.context_aware
+    def _action_before_fsfreeze(self, *args):
+        error.context("Create a file in guest.")
+        session = self._get_session(self.params, None)
+        cmd = self.params.get("gagent_fs_test_cmd")
+        self._session_cmd_close(session, cmd)
+
+
+    @error.context_aware
+    def _action_after_fsfreeze(self, *args):
+        error.context("Run live snapshot for guest.", logging.info)
+
+        image1 = self.params.get("image", "image1")
+        image_params = self.params.object_params(image1)
+        sn_params =  image_params.copy()
+        sn_params["image_name"] += "-snapshot"
+        sn_file = storage.get_image_filename(sn_params, self.test.bindir)
+        base_file = storage.get_image_filename(image_params, self.test.bindir)
+        snapshot_format = image_params.get("image_format")
+
+        self.vm.live_snapshot(base_file, sn_file, snapshot_format)
+
+
+    @error.context_aware
+    def _action_before_fsthaw(self, *args):
+        pass
+
+
+    @error.context_aware
+    def _action_after_fsthaw(self, *args):
+        error.context("Check if the file created exists in the guest.")
+        session = self._get_session(self.params, None)
+        cmd = self.params.get("gagent_fs_check_cmd")
+        s, _ = self._session_cmd_close(session, cmd)
+        if bool(s):
+            raise error.TestFail("The file created in guest is gone")
+
+        error.context("Reboot and shutdown guest.")
+        self.vm.reboot()
+        self.vm.destroy()
+
+
+def run_qemu_guest_agent_snapshot(test, params, env):
+    """
+    Freeze guest + create live snapshot + thaw guest
+
+    Test steps:
+    1) Create a big file inside guest.
+    2) Send commands in the host side to freeze guest.
+    3) Create live snapshot.
+    4) Thaw guest.
+    5) Check if the created exists in the guest.
+    6) Reboot and shutdown guest.
+
+    @param test: kvm test object
+    @param params: Dictionary with the test parameters
+    @param env: Dictionary with test environmen.
+    """
+    gagent_test = QemuGuestAgentSnapshotTest(test, params, env)
+    gagent_test.execute(test, params, env)