fix(test): split post-snapshot checks for steal time test

test_pvtime_snapshot checks that steal time reporting mechanism works
on snapshotted microVMs. This includes two checks; first that the old
steal time values are saved and restored correctly through snapshots and
second that steal time keeps increasing in microVMs resumed from a
snapshot.

The test fails intermittently, but we are not sure which of the two
invariants causes it to fail because we are checking both in the same
assertion. Split this assertion in two so that we understand better the
culprit.

Signed-off-by: Babis Chalios <[email protected]>

Author: bchalios

tests/integration_tests/functional/test_steal_time.py

@@ -104,18 +104,19 @@ def test_pvtime_snapshot(uvm_plain, microvm_factory):
     # Steal time just after restoring
     steal_after_snap = get_steal_time_ms(restored_vm)
 
-    time.sleep(2)
-
-    # Steal time after running resumed VM
-    steal_after_resume = get_steal_time_ms(restored_vm)
-
-    # Ensure steal time persisted and continued increasing
+    # Ensure steal time persisted
     tolerance = 10000  # 10.0 seconds tolerance for persistence check
     persisted = (
         steal_before < steal_after_snap and steal_after_snap - steal_before < tolerance
     )
-    increased = steal_after_resume > steal_after_snap
+    assert persisted, "Steal time did not persist through snapshot"
+
+    time.sleep(2)
+
+    # Steal time after running resumed VM
+    steal_after_resume = get_steal_time_ms(restored_vm)
 
+    # Ensure steal time continued increasing
     assert (
-        persisted and increased
-    ), "Steal time did not persist through snapshot or failed to increase after resume"
+        steal_after_resume > steal_after_snap
+    ), "Steal time failed to increase after resume"