qemu-iotests: add test for pausing a streaming operation

These check that a paused streaming job does not advance its offset.

Sometimes the new test fails; the map is different between the source
and the destination of the streaming because qemu-io does not always
pack adjacent clusters that have the same allocated/unallocated state.
However, this also happens with the existing test_stream testcase, and
is better fixed in qemu-io.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/030

@@ -18,6 +18,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+import time
 import os
 import iotests
 from iotests import qemu_img, qemu_io
@@ -98,6 +99,43 @@ class TestSingleDrive(ImageStreamingTestCase):
                          qemu_io('-c', 'map', test_img),
                          'image file map does not match backing file after streaming')
 
+    def test_stream_pause(self):
+        self.assert_no_active_streams()
+
+        result = self.vm.qmp('block-stream', device='drive0')
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm.qmp('block-job-pause', device='drive0')
+        self.assert_qmp(result, 'return', {})
+
+        time.sleep(1)
+        result = self.vm.qmp('query-block-jobs')
+        offset = self.dictpath(result, 'return[0]/offset')
+
+        time.sleep(1)
+        result = self.vm.qmp('query-block-jobs')
+        self.assert_qmp(result, 'return[0]/offset', offset)
+
+        result = self.vm.qmp('block-job-resume', device='drive0')
+        self.assert_qmp(result, 'return', {})
+
+        completed = False
+        while not completed:
+            for event in self.vm.get_qmp_events(wait=True):
+                if event['event'] == 'BLOCK_JOB_COMPLETED':
+                    self.assert_qmp(event, 'data/type', 'stream')
+                    self.assert_qmp(event, 'data/device', 'drive0')
+                    self.assert_qmp(event, 'data/offset', self.image_len)
+                    self.assert_qmp(event, 'data/len', self.image_len)
+                    completed = True
+
+        self.assert_no_active_streams()
+        self.vm.shutdown()
+
+        self.assertEqual(qemu_io('-c', 'map', backing_img),
+                         qemu_io('-c', 'map', test_img),
+                         'image file map does not match backing file after streaming')
+
     def test_stream_partial(self):
         self.assert_no_active_streams()
 
@@ -173,8 +211,6 @@ class TestStreamStop(ImageStreamingTestCase):
         os.remove(backing_img)
 
     def test_stream_stop(self):
-        import time
-
         self.assert_no_active_streams()
 
         result = self.vm.qmp('block-stream', device='drive0')