blocksd_test: check actual size for extend test

Current extend_volume_skipped test checks
only that the volume remains under the original
capacity. While this covers the usecase of
the volume not being extended to the new
capacity, it does not check that the volume
size has not changed.

We can make the check more precise with
little effort.

Fixes: a558d52
Signed-off-by: Albert Esteve <aesteve@redhat.com>

tests/storage/blocksd_test.py

@@ -1925,14 +1925,17 @@ def test_extend_volume_skipped(domain_factory, fake_task, fake_sanlock):
         srcImgUUID=sc.BLANK_UUID,
         srcVolUUID=sc.BLANK_UUID)
 
+    # Obtain the volume size before the extend call.
+    initial_vol_size = dom.getVolumeSize(img_uuid, vol_id)
+
     # Produce and extend volume to the new capacity, but we skip extends for
     # cow sparse volumes.
     vol = dom.produceVolume(img_uuid, vol_id)
     vol.extendSize(new_capacity)
 
     # Check that volume size has not changed.
-    assert dom.getVolumeSize(img_uuid, vol_id).truesize <= vol_capacity
-    assert dom.getVolumeSize(img_uuid, vol_id).apparentsize <= vol_capacity
+    vol_size = dom.getVolumeSize(img_uuid, vol_id)
+    assert vol_size == initial_vol_size
 
 
 LVM_TAG_CHARS = string.ascii_letters + "0123456789_+.-/=!:#"