Add unit tests for data_utils.py

tests/test_data_utils.py

@@ -0,0 +1,63 @@
+import pytest
+import numpy as np
+from datetime import datetime, timedelta
+from astropy import units as u
+from unittest.mock import patch
+
+from WeatherRoutingTool.algorithms.data_utils import get_closest, get_speed_from_arrival_time
+
+@pytest.fixture
+def sample_array():
+    return np.array([10.5, 20.0, 30.5, 40.0, 50.5])
+
+@pytest.fixture
+def route_lons():
+    return np.array([10.0, 11.0, 12.0])
+
+@pytest.fixture
+def route_lats():
+    return np.array([50.0, 51.0, 52.0])
+
+@pytest.fixture
+def departure_time():
+    return datetime(2023, 1, 1, 12, 0, 0)
+
+@pytest.fixture
+def arrival_time():
+    return datetime(2023, 1, 2, 12, 0, 0) # 24 hours later
+
+@pytest.mark.parametrize(
+    "target_value, expected_index",
+    [
+        (10.0, 0),    # Closest to 10.5
+        (20.1, 1),    # Closest to 20.0
+        (45.0, 3),    # Closter to 40.0 than 50.5
+        (100.0, 4),   # Beyond max
+        (0.0, 0),     # Below min
+    ]
+)
+def test_get_closest(sample_array, target_value, expected_index):
+    assert get_closest(sample_array, target_value) == expected_index
+
+@pytest.mark.parametrize(
+    "dist_values, expected_speed_mps",
+    [
+        ([50000, 50000], 100000 / (24 * 3600)), # 100km over 24 hours
+        ([100000, 200000], 300000 / (24 * 3600)), 
+        ([0, 0], 0.0),
+    ]
+)
+@patch('WeatherRoutingTool.algorithms.data_utils.RouteParams.get_per_waypoint_coords')
+def test_get_speed_from_arrival_time(mock_get_coords, route_lons, route_lats, departure_time, arrival_time, dist_values, expected_speed_mps):
+    mock_get_coords.return_value = {
+        'dist': np.array(dist_values) * u.meter
+    }
+
+    speed = get_speed_from_arrival_time(route_lons, route_lats, departure_time, arrival_time)
+
+    # Check if the mock was called correctly
+    mock_get_coords.assert_called_once()
+
+    # The expected speed should be close
+    assert np.isclose(speed.value, expected_speed_mps)
+    assert speed.unit == u.meter / u.second