diff --git a/README.md b/README.md
index ab3013a..0fb4532 100644
--- a/README.md
+++ b/README.md
@@ -2,8 +2,7 @@
 
 > note: this is alpha software; apis may change quickly, and quality of the brightness prediction is still being ironed out
 
-CTTS is an open source application for reading [sky brightness](https://en.wikipedia.org/wiki/Sky_brightness) all over the
-earth, without a sensor.
+CTTS is an open source application for reading [sky brightness](https://en.wikipedia.org/wiki/Sky_brightness) all over the earth's landmass, without a sensor.
 
 ## features
 
diff --git a/pp/pp/cells/cell_covering.py b/pp/pp/cells/cell_covering.py
index 280ba36..4fca855 100644
--- a/pp/pp/cells/cell_covering.py
+++ b/pp/pp/cells/cell_covering.py
@@ -8,7 +8,10 @@
 from ..config import resolution
 
 class CellCovering:
-    def __init__(self, path_to_geojson: Path = Path(__file__).parent / "land.geojson"):
+    def __init__(self, path_to_geojson: Path | None = None):
+        if path_to_geojson is None:
+            path_to_geojson = Path(__file__).parent / "land.geojson"
+
         with open(path_to_geojson, "r") as file:
             geojson = json.load(file)
 
diff --git a/pp/pp/cells/cell_publisher.py b/pp/pp/cells/cell_publisher.py
index b026fd8..79bd980 100644
--- a/pp/pp/cells/cell_publisher.py
+++ b/pp/pp/cells/cell_publisher.py
@@ -3,6 +3,7 @@
 import typing
 from datetime import datetime, timezone
 from collections import defaultdict
+from pathlib import Path
 
 import grpc
 from h3 import h3_to_geo
@@ -21,8 +22,8 @@ class CellPublisher(CellCovering):
     cell_counts = defaultdict(int)
 
     def __init__(self, api_host: str, api_port: int, channel: BlockingChannel,
-                 prediction_queue: str, cycle_queue: str):
-        super().__init__()
+                 prediction_queue: str, cycle_queue: str, path_to_geojson: Path | None = None):
+        super().__init__(path_to_geojson=path_to_geojson)
 
         self._prediction_queue = prediction_queue
         self._cycle_queue = cycle_queue
@@ -67,10 +68,10 @@ def publish_cycle_completion_message(self, start: datetime, end: datetime) -> No
 
     def run(self):
         cells = self.covering
-        if len(cells) == 0:
+        if not cells:
             raise ValueError("cell covering is empty!")
-        log.info(f"publishing brightness for {len(cells)} cells(s)")
 
+        log.info(f"publishing brightness for {len(cells)} cells(s) resoulution {resolution}")
         while True:
             start_time_utc = datetime.now(timezone.utc)
 
diff --git a/pp/tests/empty.geojson b/pp/tests/empty.geojson
new file mode 100644
index 0000000..8b3698f
--- /dev/null
+++ b/pp/tests/empty.geojson
@@ -0,0 +1,4 @@
+{
+  "type": "FeatureCollection",
+  "features": []
+}
diff --git a/pp/tests/fixtures.py b/pp/tests/fixtures.py
index 4b2390b..f9aa16e 100644
--- a/pp/tests/fixtures.py
+++ b/pp/tests/fixtures.py
@@ -1,4 +1,5 @@
 from unittest.mock import MagicMock
+from pathlib import Path
 import uuid
 
 import pytest
@@ -33,7 +34,7 @@ def mock_pika_channel(mocker):
 
 
 @pytest.fixture
-def publisher(mock_grpc_client, mock_pika_channel):
+def cell_publisher(mock_grpc_client, mock_pika_channel):
     return CellPublisher(api_host="localhost",
                          api_port=50051,
                          channel=mock_pika_channel,
diff --git a/pp/tests/test_publisher.py b/pp/tests/test_publisher.py
index 0630881..a67a8e3 100644
--- a/pp/tests/test_publisher.py
+++ b/pp/tests/test_publisher.py
@@ -1,22 +1,29 @@
 from datetime import datetime, timedelta
 
+import h3
 import pytest
 from .fixtures import *
 
-@pytest.mark.parametrize("cell_id", [
-    ("89283082813ffff"),
-    ("8928308280fffff"),
-    ("89283082807ffff"),
-])
-def test_can_publish_cell_brightness(cell_id, publisher, mock_pika_channel):
-    publisher.publish_cell_brightness_message(cell_id)
+@pytest.mark.parametrize("cell_id", [x for x in h3.get_res0_indexes()])
+def test_can_publish_cell_brightness_at_h3_indexes(cell_id, cell_publisher, mock_pika_channel):
+    cell_publisher.publish_cell_brightness_message(cell_id)
     mock_pika_channel.basic_publish.assert_called_once()
 
-@pytest.mark.parametrize("minutes_ago", [
-    (i) for i in range(1, 10)
-])
-def test_can_publish_cycle_complete(minutes_ago, publisher, mock_pika_channel):
+@pytest.mark.parametrize("minutes_ago", [i for i in range(1, 10)])
+def test_can_publish_cycle_complete(minutes_ago, cell_publisher, mock_pika_channel):
     then = datetime.now() - timedelta(minutes=minutes_ago)
     now = datetime.now()
-    publisher.publish_cycle_completion_message(then, now)
+    cell_publisher.publish_cycle_completion_message(then, now)
     mock_pika_channel.basic_publish.assert_called_once()
+
+def test_publisher_raises_on_empty_cells(mock_grpc_client, mock_pika_channel):
+    with pytest.raises(ValueError):
+        cell_publisher = CellPublisher(
+            api_host="localhost",
+            api_port=50051,
+            channel=mock_pika_channel,
+            prediction_queue="prediction",
+            cycle_queue="cycle",
+            path_to_geojson=Path(__file__).parent / "empty.geojson"
+        )
+        cell_publisher.run()