diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..98aed8a
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,35 @@
+from pathlib import Path
+
+import pytest
+import yaml
+
+from simulator.__main__ import _build_world
+from simulator.core.carrier import Carrier
+from simulator.core.greenhouse import Greenhouse, Node
+from simulator.core.spider import Spider
+from simulator.core.world import World
+from simulator.dtn.epidemic import EpidemicRouter
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+@pytest.fixture
+def small_world() -> World:
+    n0 = Node(id="n0", x=0.0, y=0.0, hotspot=0.0)
+    n1 = Node(id="n1", x=1.0, y=0.0, hotspot=0.0)
+    greenhouse = Greenhouse(width=5, height=5, nodes=[n0, n1], edges=[("n0", "n1")])
+    spiders = [Spider(id="S0", node=n0, storage_capacity=1_000_000)]
+    carriers = [Carrier(id="C0", node=n0, storage_capacity=10_000_000)]
+    return World(
+        greenhouse=greenhouse,
+        spiders=spiders,
+        carriers=carriers,
+        router=EpidemicRouter(),
+    )
+
+
+@pytest.fixture
+def loaded_world() -> World:
+    with (ROOT / "simulator/config/default.yaml").open(encoding="utf-8") as config_file:
+        return _build_world(yaml.safe_load(config_file))
+
diff --git a/tests/test_world.py b/tests/test_world.py
index d39265a..59871e8 100644
--- a/tests/test_world.py
+++ b/tests/test_world.py
@@ -1,40 +1,30 @@
-from simulator.core.carrier import Carrier
-from simulator.core.greenhouse import Greenhouse, Node
-from simulator.core.spider import Spider
 from simulator.core.world import World
-from simulator.dtn.epidemic import EpidemicRouter
 
 
-def _simple_world() -> World:
-    n0 = Node(id="n0", x=0.0, y=0.0, hotspot=0.0)
-    n1 = Node(id="n1", x=1.0, y=0.0, hotspot=0.0)
-    gh = Greenhouse(width=5, height=5, nodes=[n0, n1], edges=[("n0", "n1")])
-    spiders  = [Spider(id="S0", node=n0, storage_capacity=1_000_000)]
-    carriers = [Carrier(id="C0", node=n0, storage_capacity=10_000_000)]
-    return World(greenhouse=gh, spiders=spiders, carriers=carriers, router=EpidemicRouter())
+def test_world_step_increments_tick(small_world: World):
+    small_world.step()
+    assert small_world.tick == 1
 
 
-def test_world_step_increments_tick():
-    world = _simple_world()
-    world.step()
-    assert world.tick == 1
-
-
-def test_spider_accumulates_data_over_time():
-    world = _simple_world()
+def test_spider_accumulates_data_over_time(small_world: World):
     for _ in range(10):
-        world.step()
-    assert world.spiders[0].storage_used > 0
+        small_world.step()
+    assert small_world.spiders[0].storage_used > 0
 
 
-def test_carrier_receives_dump_when_in_range():
-    world = _simple_world()
-    spider  = world.spiders[0]
-    carrier = world.carriers[0]
+def test_carrier_receives_dump_when_in_range(small_world: World):
+    spider = small_world.spiders[0]
+    carrier = small_world.carriers[0]
     # Force spider onto carrier's node and fill storage
     spider.node = carrier.node
     spider.storage_used = spider.storage_capacity * 0.8
     initial_carrier_storage = carrier.storage_used
-    world._run_wifi_dumps()
+    small_world._run_wifi_dumps()
     assert carrier.storage_used > initial_carrier_storage
     assert spider.storage_ratio < 0.8
+
+
+def test_loaded_world_uses_default_config(loaded_world: World):
+    assert loaded_world.greenhouse.nodes
+    assert loaded_world.spiders
+    assert loaded_world.carriers