add tests

pvanalytics/features/snow.py

@@ -132,9 +132,9 @@ def get_transmission(measured_e_e, modeled_e_e, i_mp):
        50th Photovoltaic Specialists Conference (PVSC), San Juan, PR, USA,
        2023, pp. 1-5. :doi:`10.1109/PVSC48320.2023.10360065`
     """
-
+    # TODO only works with Series
     T = modeled_e_e/measured_e_e
-    T[T.isna()] = np.nan
+    T[T.isna()] = np.nan  # TODO what does this accomplish
     T[i_mp == 0] = 0
     T[T < 0] = np.nan
     T[T > 1] = 1

pvanalytics/tests/features/test_snow.py

@@ -7,10 +7,11 @@
 import numpy as np
 import pandas as pd
 from numpy.testing import assert_array_equal
+from pandas.testing import assert_series_equal
 from pvanalytics.features import snow
 
 
-def test_horizon_mask():
+def test_get_horizon_mask():
     horizon = pd.Series(index=range(0, 360), data=0)
     horizon[5:10] = 10
     result = snow.get_horizon_mask(horizon, azimuth=np.array([4, 5, 7]),
@@ -19,6 +20,51 @@ def test_horizon_mask():
     assert_array_equal(result, expected)
 
 
+def test_get_irradiance_sapm():
+    # solve Ee^2 + 2 Ee - 3 = 0
+    c0, c1 = (2, 1)
+    imp0 = 6.
+    alpha_imp = -2. / 3
+    temp_cell = 26.
+    # effective irradiance = i_mp / factor
+    i_mp = np.array([6., 0., np.nan])
+    result = snow.get_irradiance_sapm(temp_cell, i_mp, imp0, c0, c1, alpha_imp)
+    expected = np.array([1000., 0., np.nan])  # from suns to W/m2
+    assert_array_equal(result, expected)
+    # test with Series
+    i_mp = pd.Series(data=i_mp)
+    temp_cell = pd.Series(index=i_mp.index, data=26.)
+    result = snow.get_irradiance_sapm(temp_cell, i_mp, imp0, c0, c1, alpha_imp)
+    assert_series_equal(result, pd.Series(index=i_mp.index, data=expected))
+
+
+def test_get_irradiance_imp():
+    # solve Ee = Imp / Imp0
+    imp0 = 6.
+    i_mp = np.array([6., 0., np.nan])
+    result = snow.get_irradiance_imp(i_mp, imp0)
+    expected = np.array([1000., 0, np.nan])
+    assert_array_equal(result, expected)
+    # test with Series
+    i_mp = pd.Series(data=i_mp)
+    result = snow.get_irradiance_imp(i_mp, imp0)
+    assert_series_equal(result, pd.Series(index=i_mp.index, data=expected))
+
+
+def test_get_transmission():
+    # solve modeled_ee / measured_ee, subject to i_mp>0, with bounds
+    # T[T.isna()] = np.nan
+    # T[i_mp == 0] = 0
+    # T[T < 0] = np.nan
+    # T[T > 1] = 1
+    measured_ee = pd.Series(data=[1., 0.5, 1., -1., np.nan])
+    modeled_ee = pd.Series(data=[1., 1., 1., 1., 1.])
+    i_mp = pd.Series(data=[1., 1., 0., 1., 1.])
+    result = snow.get_transmission(measured_ee, modeled_ee, i_mp)
+    expected = pd.Series(data=[1., 1., 0., np.nan, np.nan])
+    assert_series_equal(result, expected)
+
+
 def test_categorize():
     vmp_ratio = np.array([np.nan, 0.9, 0.1, 0.6, 0.7, 0.9, 0.9])
     voltage = np.array([400., 400., 400., 400., 400., 400., 200.])