New case of cache_sizes_test

Test different cache sizes in a guest.
Signed-off-by: NTingting Mao <timao@redhat.com>

qemu/tests/cache_sizes_test.py

+import logging
+
+from provider import qemu_img_utils as img_utils
+
+
+def run(test, params, env):
+    """
+    Cache sizes test for a guest.
+
+    1. Boot a guest up with different cache sizes.
+    2. Check writing data to the guest works fine.
+    3. Shut the guest down.
+
+    :param test: Qemu test object
+    :param params: Dictionary with the test parameters
+    :param env: Dictionary with test environment
+    """
+    file = params["guest_file_name"]
+    initial_tag = params["images"]
+    cache_sizes = params["cache_sizes"].split()
+
+    logging.info("Boot a guest up from initial image: %s, and create a"
+                 " file %s on the disk.", initial_tag, file)
+    for cache_size in cache_sizes:
+        params["drv_extra_params"] = "cache-size=%s" % cache_size
+        vm = img_utils.boot_vm_with_images(test, params, env)
+        session = vm.wait_for_login()
+        guest_temp_file = params["guest_file_name"]
+        sync_bin = params.get("sync_bin", "sync")
+
+        logging.debug("Create temporary file on guest: %s", guest_temp_file)
+        img_utils.save_random_file_to_vm(vm, guest_temp_file, 2048 * 512,
+                                         sync_bin)
+
+        session.close()
+        vm.destroy()

qemu/tests/cfg/cache_sizes_test.cfg

+- cache_sizes_test:
+    only qcow2
+    virt_test_type = qemu
+    type = cache_sizes_test
+    start_vm = no
+    kill_vm = yes
+    force_create_image = no
+    tmp_dir = /var/tmp
+    tmp_file_name = ${tmp_dir}/testfile
+    guest_file_name = ${tmp_file_name}
+    cache_sizes = "0 2 1024 65525 65527"
+    Windows:
+        guest_file_name = C:\testfile
+        x86_64:
+            sync_bin = WIN_UTILS:\Sync\sync64.exe /accepteula
+        i386, i686:
+            sync_bin = WIN_UTILS:\Sync\sync.exe /accepteula