diff --git a/tests/test_gridded.py b/tests/test_gridded.py
new file mode 100644
index 0000000..0f90739
--- /dev/null
+++ b/tests/test_gridded.py
@@ -0,0 +1,27 @@
+import pytest
+import os
+import xarray as xr
+from halodrops.processor import Gridded
+
+sondes = None
+flight_id = "20240811"
+platform_id = "HALO"
+l3_default = f"{platform_id}_{flight_id}_Level_3.nc"
+l3_template = "{flight_id}_{platform}_Level_3.nc"
+
+
+@pytest.fixture
+def gridded():
+    return Gridded(sondes, flight_id=flight_id, platform_id=platform_id)
+
+
+def test_l3_default(gridded):
+    gridded.get_l3_filename()
+    assert gridded.l3_filename == l3_default
+
+
+def test_l3_template(gridded):
+    gridded.get_l3_filename(l3_filename_template=l3_template)
+    assert gridded.l3_filename == l3_template.format(
+        flight_id=flight_id, platform=platform_id
+    )