try out skipping chandrupatla on py3.9

Author: kandersolar

tests/conftest.py

@@ -4,6 +4,7 @@
 
 import pandas as pd
 import os
+import sys
 from packaging.version import Version
 import pytest
 from functools import wraps
@@ -194,6 +195,17 @@ def has_spa_c():
                                          reason="requires pandas>=2.0.0")
 
 
+# single-diode equation functions have method=='chandrupatla', which relies
+# on scipy.optimize.elementwise.find_root, which is only available in
+# scipy>=1.15.  That is only available for python 3.10 and above, so
+# we need to skip those tests on python 3.9.
+# TODO remove this when we drop support for python 3.9.
+chandrupatla_available = sys.version_info >= (3, 10)
+chandrupatla = pytest.param(
+    "chandrupatla", marks=pytest.mark.skipif(not chandrupatla_available)
+)
+
+
 @pytest.fixture()
 def golden():
     return Location(39.742476, -105.1786, 'America/Denver', 1830.14)

tests/test_pvsystem.py

@@ -22,6 +22,8 @@
 
 from tests.test_singlediode import get_pvsyst_fs_495
 
+from .conftest import chandrupatla, chandrupatla_available
+
 
 @pytest.mark.parametrize('iam_model,model_params', [
     ('ashrae', {'b': 0.05}),
@@ -1371,8 +1373,11 @@ def fixture_i_from_v(request):
 
 
 @pytest.mark.parametrize(
-    'method, atol', [('lambertw', 1e-11), ('brentq', 1e-11), ('newton', 1e-11),
-                     ('chandrupatla', 1e-11)]
+    'method, atol', [
+        ('lambertw', 1e-11), ('brentq', 1e-11), ('newton', 1e-11),
+        pytest.param("chandrupatla", 1e-11,
+                     marks=pytest.mark.skipif(not chandrupatla_available)),
+    ]
 )
 def test_i_from_v(fixture_i_from_v, method, atol):
     # Solution set loaded from fixture
@@ -1401,50 +1406,42 @@ def test_PVSystem_i_from_v(mocker):
     m.assert_called_once_with(*args)
 
 
-def test_i_from_v_size():
-    with pytest.raises(ValueError):
-        pvsystem.i_from_v([7.5] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5)
-    with pytest.raises(ValueError):
-        pvsystem.i_from_v([7.5] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5,
-                          method='brentq')
-    with pytest.raises(ValueError):
-        pvsystem.i_from_v([7.5] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5,
-                          method='chandrupatla')
+@pytest.mark.parametrize('method', ['lambertw', 'brentq', 'newton',
+                                    chandrupatla])
+def test_i_from_v_size(method):
+    if method == 'newton':
+        args = ([7.5] * 3, np.array([7., 7.]), 6e-7, 0.1, 20, 0.5)
+    else:
+        args = ([7.5] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5)
     with pytest.raises(ValueError):
-        pvsystem.i_from_v([7.5] * 3, np.array([7., 7.]), 6e-7, 0.1, 20, 0.5,
-                          method='newton')
+        pvsystem.i_from_v(*args, method=method)
 
 
-def test_v_from_i_size():
-    with pytest.raises(ValueError):
-        pvsystem.v_from_i([3.] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5)
-    with pytest.raises(ValueError):
-        pvsystem.v_from_i([3.] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5,
-                          method='brentq')
-    with pytest.raises(ValueError):
-        pvsystem.v_from_i([3.] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5,
-                          method='chandrupatla')
+@pytest.mark.parametrize('method', ['lambertw', 'brentq', 'newton',
+                                    chandrupatla])
+def test_v_from_i_size(method):
+    if method == 'newton':
+        args = ([3.] * 3, np.array([7., 7.]), 6e-7, [0.1], 20, 0.5)
+    else:
+        args = ([3.] * 3, 7., 6e-7, [0.1] * 2, 20, 0.5)
     with pytest.raises(ValueError):
-        pvsystem.v_from_i([3.] * 3, np.array([7., 7.]), 6e-7, [0.1], 20, 0.5,
-                          method='newton')
+        pvsystem.v_from_i(*args, method=method)
 
 
-def test_mpp_floats():
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
+def test_mpp_floats(method):
     """test max_power_point"""
     IL, I0, Rs, Rsh, nNsVth = (7, 6e-7, .1, 20, .5)
-    out = pvsystem.max_power_point(IL, I0, Rs, Rsh, nNsVth, method='brentq')
+    out = pvsystem.max_power_point(IL, I0, Rs, Rsh, nNsVth, method=method)
     expected = {'i_mp': 6.1362673597376753,  # 6.1390251797935704, lambertw
                 'v_mp': 6.2243393757884284,  # 6.221535886625464, lambertw
                 'p_mp': 38.194210547580511}  # 38.194165464983037} lambertw
     assert isinstance(out, dict)
     for k, v in out.items():
         assert np.isclose(v, expected[k])
-    out = pvsystem.max_power_point(IL, I0, Rs, Rsh, nNsVth, method='newton')
-    for k, v in out.items():
-        assert np.isclose(v, expected[k])
 
 
-@pytest.mark.parametrize('method', ['brentq', 'newton', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
 def test_mpp_recombination(method):
     """test max_power_point"""
     pvsyst_fs_495 = get_pvsyst_fs_495()
@@ -1475,7 +1472,7 @@ def test_mpp_recombination(method):
         assert np.isclose(v, expected[k], 0.01)
 
 
-@pytest.mark.parametrize('method', ['brentq', 'newton', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
 def test_mpp_array(method):
     """test max_power_point"""
     IL, I0, Rs, Rsh, nNsVth = (np.array([7, 7]), 6e-7, .1, 20, .5)
@@ -1488,7 +1485,7 @@ def test_mpp_array(method):
         assert np.allclose(v, expected[k])
 
 
-@pytest.mark.parametrize('method', ['brentq', 'newton', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
 def test_mpp_series(method):
     """test max_power_point"""
     idx = ['2008-02-17T11:30:00-0800', '2008-02-17T12:30:00-0800']

tests/test_singlediode.py

@@ -12,11 +12,13 @@
 from numpy.testing import assert_array_equal
 from .conftest import TESTS_DATA_DIR
 
+from .conftest import chandrupatla, chandrupatla_available
+
 POA = 888
 TCELL = 55
 
 
-@pytest.mark.parametrize('method', ['brentq', 'newton', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
 def test_method_spr_e20_327(method, cec_module_spr_e20_327):
     """test pvsystem.singlediode with different methods on SPR-E20-327"""
     spr_e20_327 = cec_module_spr_e20_327
@@ -38,7 +40,7 @@ def test_method_spr_e20_327(method, cec_module_spr_e20_327):
     assert np.isclose(pvs['i_xx'], out['i_xx'])
 
 
-@pytest.mark.parametrize('method', ['brentq', 'newton', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['brentq', 'newton', chandrupatla])
 def test_newton_fs_495(method, cec_module_fs_495):
     """test pvsystem.singlediode with different methods on FS495"""
     fs_495 = cec_module_fs_495
@@ -147,7 +149,7 @@ def precise_iv_curves(request):
 
 
 @pytest.mark.parametrize('method', ['lambertw', 'brentq', 'newton',
-                                    'chandrupatla'])
+                                    chandrupatla])
 def test_singlediode_precision(method, precise_iv_curves):
     """
     Tests the accuracy of singlediode. ivcurve_pnts is not tested.
@@ -189,7 +191,7 @@ def test_singlediode_lambert_negative_voc(mocker):
 
 
 @pytest.mark.parametrize('method', ['lambertw', 'brentq', 'newton',
-                                    'chandrupatla'])
+                                    chandrupatla])
 def test_v_from_i_i_from_v_precision(method, precise_iv_curves):
     """
     Tests the accuracy of pvsystem.v_from_i and pvsystem.i_from_v.
@@ -258,7 +260,7 @@ def get_pvsyst_fs_495():
         )
     ]
 )
-@pytest.mark.parametrize('method', ['newton', 'brentq', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['newton', 'brentq', chandrupatla])
 def test_pvsyst_recombination_loss(method, poa, temp_cell, expected, tol):
     """test PVSst recombination loss"""
     pvsyst_fs_495 = get_pvsyst_fs_495()
@@ -350,7 +352,7 @@ def test_pvsyst_recombination_loss(method, poa, temp_cell, expected, tol):
         )
     ]
 )
-@pytest.mark.parametrize('method', ['newton', 'brentq', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['newton', 'brentq', chandrupatla])
 def test_pvsyst_breakdown(method, brk_params, recomb_params, poa, temp_cell,
                           expected, tol):
     """test PVSyst recombination loss"""
@@ -460,6 +462,7 @@ def bishop88_arguments():
         'maxiter': 30,
     }),
     # can't include chandrupatla since the function is not available to patch
+    # TODO: add this once chandrupatla becomes non-optional functionality
     #('chandrupatla', {
     #    'tolerances ': {'xtol': 1e-8, 'rtol': 1e-8},
     #    'maxiter': 30,
@@ -503,12 +506,12 @@ def test_bishop88_kwargs_transfer(method, method_kwargs, mocker,
         'maxiter': 20,
         '_inexistent_param': "0.01"
     }),
-    ('chandrupatla', {
+    pytest.param('chandrupatla', {
         'xtol': 1e-4,
         'rtol': 1e-4,
         'maxiter': 20,
         '_inexistent_param': "0.01"
-    }),
+    }, marks=pytest.mark.skipif(not chandrupatla_available)),
 ])
 def test_bishop88_kwargs_fails(method, method_kwargs, bishop88_arguments):
     """test invalid method_kwargs passed onto the optimizer fail"""
@@ -526,7 +529,7 @@ def test_bishop88_kwargs_fails(method, method_kwargs, bishop88_arguments):
                   method_kwargs=method_kwargs)
 
 
-@pytest.mark.parametrize('method', ['newton', 'brentq', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['newton', 'brentq', chandrupatla])
 def test_bishop88_full_output_kwarg(method, bishop88_arguments):
     """test call to bishop88_.* with full_output=True return values are ok"""
     method_kwargs = {'full_output': True}
@@ -560,7 +563,7 @@ def test_bishop88_full_output_kwarg(method, bishop88_arguments):
     assert len(ret_val[1]) >= 2
 
 
-@pytest.mark.parametrize('method', ['newton', 'brentq', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['newton', 'brentq', chandrupatla])
 def test_bishop88_pdSeries_len_one(method, bishop88_arguments):
     for k, v in bishop88_arguments.items():
         bishop88_arguments[k] = pd.Series([v])
@@ -576,7 +579,7 @@ def _sde_check_solution(i, v, il, io, rs, rsh, a, d2mutau=0., NsVbi=np.inf):
     return il - io*np.expm1(vd/a) - vd/rsh - il*d2mutau/(NsVbi - vd) - i
 
 
-@pytest.mark.parametrize('method', ['newton', 'brentq', 'chandrupatla'])
+@pytest.mark.parametrize('method', ['newton', 'brentq', chandrupatla])
 def test_bishop88_init_cond(method):
     # GH 2013
     p = {'alpha_sc': 0.0012256,