diff --git a/tests/test_core.py b/tests/test_core.py
index 22da9f8..4882fb9 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -236,13 +236,14 @@ def test_schedule_at_time(self):
     def test_run_until(self):
         """Test running until specific time."""
         sim = Simulation()
+        sim.schedule(lambda: None, delay=101.0)  # Need at least one event past end time
         sim.run(until=100.0)
         assert sim.now == 100.0
 
     def test_run_for_duration(self):
         """Test running for duration."""
         sim = Simulation()
-        sim.schedule(lambda: None, delay=0)  # Need at least one event
+        sim.schedule(lambda: None, delay=51.0)  # Need at least one event past end time
         sim.run(for_duration=50.0)
         assert sim.now == 50.0
 
diff --git a/tests/test_resources.py b/tests/test_resources.py
index 31fd8f4..e1aacae 100644
--- a/tests/test_resources.py
+++ b/tests/test_resources.py
@@ -3,7 +3,7 @@
 """
 
 import pytest
-from simcraft.core.simulation import Simulation
+from simcraft.core.simulation import Simulation, SimulationConfig
 from simcraft.core.entity import Entity
 from simcraft.resources.queue import Queue, PriorityQueue
 from simcraft.resources.server import Server
@@ -258,7 +258,7 @@ def test_queueing(self):
 
     def test_random_service_time(self):
         """Test random service time function."""
-        sim = Simulation(config={"seed": 42})
+        sim = Simulation(config=SimulationConfig(seed=42))
 
         def random_service():
             return sim.rng.exponential(5.0)