diff --git a/test/common/infrastructure.py b/test/common/infrastructure.py
index 145b1109f..966c61d3e 100644
--- a/test/common/infrastructure.py
+++ b/test/common/infrastructure.py
@@ -133,7 +133,7 @@ def _wrapping_function(self):
                     # forward to amaranth
                     yield
                 # Do early forward to amaranth
-                if not isinstance(command, CoreblocksCommand):
+                elif not isinstance(command, CoreblocksCommand):
                     # Pass everything else to amaranth simulator without modifications
                     response = yield command
                 elif isinstance(command, Now):
@@ -196,7 +196,8 @@ def run_until_with_callbacks(self, deadline, *, run_passive=False):
         """
         # Convert deadline in seconds into internal amaranth 1 ps units
         deadline = deadline * 1e12
-        while cast(Any, self)._engine.now < deadline and (self.advance() or run_passive):
+        assert cast(Any,self)._engine.now <= deadline
+        while (self.advance() or run_passive) and cast(Any,self)._engine.now < deadline:
             for callback in self.one_shot_callbacks:
                 callback()
             self.one_shot_callbacks.clear()