feat: Test distance calculation

src/tests/test_geo.py

@@ -0,0 +1,24 @@
+from fellchensammlung.tools.geo import calculate_distance_between_coordinates
+from django.test import TestCase
+
+
+class DistanceTest(TestCase):
+    accuracy = 1.05  # 5% off is ok
+
+    def test_calculate_distance_between_coordinates(self):
+        coordinates_berlin = (52.50327,13.41238)
+        coordinates_stuttgart = (48.77753579028781, 9.185250111016634)
+        coordinates_weil_im_dorf = (48.813691653929276, 9.112217733791029)
+        coordinates_with_distance = {"berlin_stuttgart": (coordinates_berlin, coordinates_stuttgart, 510),
+                                     "stuttgart_berlin": (coordinates_stuttgart, coordinates_berlin, 510),
+                                     "stuttgart_weil": (coordinates_stuttgart, coordinates_weil_im_dorf, 6.7),
+                                     }
+        for key in coordinates_with_distance:
+            (a, b, distance) = coordinates_with_distance[key]
+            result = calculate_distance_between_coordinates(a, b)
+            try:
+                self.assertLess(result, distance * self.accuracy)
+                self.assertGreater(result, distance / self.accuracy)
+            except AssertionError as e:
+                print(f"Distance calculation failed. Expected {distance}, got {result}")
+                raise e