added qemu_img_info_while_vm_running cases

Added three `qemu-img` lock tests.
To verify it supports to get information of a running image.
Signed-off-by: NHaotong Chen <hachen@redhat.com>

qemu/tests/cfg/qemu_img_info_while_running.cfg

+- qemu_img_info_while_vm_running:
+    virt_test_type = qemu
+    kill_vm = yes
+    start_vm = no
+    force_create_image = no
+    type = qemu_img_info_while_vm_running
+    image_chain = "image1 sn"
+    image_name_sn = "images/sn"
+    image_format_sn = "qcow2"
+    create_snapshot = yes
+    variants:
+        - boot_with_base_info_snapshot:
+            only qcow2
+        - boot_with_snapshot_info_base:
+            only qcow2
+            boot_with_snapshot = yes
+        - boot_and_info_same_img:
+            only raw
+            create_snapshot = no

qemu/tests/qemu_disk_img.py

@@ -209,3 +209,18 @@ class QemuImgTest(qemu_storage.QemuImg):
 
 def run(test, params, env):
     pass
+
+
+def generate_base_snapshot_pair(image_chain):
+    """
+    Generate base and snapshot pairs according to param["image_chain"].
+
+    :param image_chain: param["image_chain"]
+    """
+    image_chain = image_chain.split()
+    n = len(image_chain)
+    if n < 2:
+        raise ValueError("Image_chain should contain at"
+                         "least 2 items, got %s." % n)
+    for i in range(1, n):
+        yield [image_chain[i - 1], image_chain[i]]

qemu/tests/qemu_img_info_while_vm_running.py

+import logging
+
+from avocado.utils import process
+from virttest import data_dir
+from virttest import error_context
+from virttest.qemu_storage import QemuImg
+
+from qemu.tests.qemu_disk_img import QemuImgTest
+from qemu.tests.qemu_disk_img import generate_base_snapshot_pair
+
+
+@error_context.context_aware
+def run(test, params, env):
+    """
+    'qemu-img' lock tests.
+
+    Verify it supports to get information of a running image.
+    Including three tests:
+    1. Create a raw image.
+       Boot vm using this image.
+       'qemu-info' the image.
+    2. Create a base qcow2 image.
+       Create an external snapshot.
+       Boot vm using the base.
+       'qemu-info' the snapshot.
+    3. Create a base qcow2 image.
+       Create an external snapshot.
+       Boot vm using the snapshot.
+       'qemu-info' the base.
+
+    :param test: Qemu test object
+    :param params: Dictionary with the test parameters
+    :param env: Dictionary with test environment.
+    """
+    def _boot_vm(boot_img):
+        error_context.context("Boot vm with %s." % boot_img, logging.info)
+        vm.params["images"] = boot_img
+        vm.create()
+        vm.verify_alive()
+
+    def _qemu_img_info(info_img):
+        error_context.context("Check qemu-img info with %s." % info_img,
+                              logging.info)
+        img_param = params.object_params(info_img)
+        img = QemuImg(img_param, data_dir.get_data_dir(), info_img)
+        try:
+            img.info()
+        except process.CmdError:
+            test.fail("qemu-img info %s failed." % info_img)
+
+    def _qemu_img_info_while_vm_running(boot_img, info_img):
+        _boot_vm(boot_img)
+        _qemu_img_info(info_img)
+
+    vm = env.get_vm(params["main_vm"])
+    if params.get("create_snapshot", "no") == "yes":
+        # create an external snapshot
+        gen = generate_base_snapshot_pair(params["image_chain"])
+        base_snapshot_pair = base, snapshot = next(gen)
+        # workaround to assign system disk's image_name to image_name_image1
+        params["image_name_image1"] = params["image_name"]
+        qit = QemuImgTest(test, params, env, snapshot)
+        qit.create_snapshot()
+
+        if params.get("boot_with_snapshot", "no") == "yes":
+            # reverse base snap pair, so boot vm with snapshot
+            base_snapshot_pair.reverse()
+        _qemu_img_info_while_vm_running(*base_snapshot_pair)
+    else:
+        # boot and info same img, raw only
+        _qemu_img_info_while_vm_running("image1", "image1")