Refactor Huld model tests for EU JRC coefficients

- Updated the test for the Huld model to use non-reference values for irradiance and temperature.
- Enhanced the test to verify that results differ for all supported cell types when using EU JRC coefficients.
- Added checks to ensure all cell types are supported and that a KeyError is raised for invalid cell types.

(cherry picked from commit 7c0feba)

Author: OmarBahamida

tests/test_pvarray.py

@@ -74,24 +74,18 @@ def test_huld():
 def test_huld_eu_jrc():
     """Test the EU JRC updated coefficients for the Huld model."""
     pdc0 = 100
-    
-    # Test that EU JRC coefficients give different results than original
-    res_orig = pvarray.huld(1000, 25, pdc0, cell_type='cSi')
-    res_eu_jrc = pvarray.huld(1000, 25, pdc0, cell_type='cSi', use_eu_jrc=True)
-    assert not np.isclose(res_orig, res_eu_jrc)
-    
-    # Test that coefficients are properly scaled by pdc0
-    k_orig = pvarray._infer_k_huld('cSi', pdc0)
-    k_eu_jrc = pvarray._infer_k_huld_eu_jrc('cSi', pdc0)
-    assert len(k_orig) == len(k_eu_jrc) == 6
-    assert all(np.isclose(k1/pdc0, k2/pdc0) for k1, k2 in zip(k_orig, k_eu_jrc))
-    
-    # Test that all cell types are supported
-    for cell_type in ['csi', 'cis', 'cdte']:
-        k = pvarray._infer_k_huld_eu_jrc(cell_type, pdc0)
-        assert len(k) == 6
-        assert all(isinstance(x, float) for x in k)
-    
-    # Test invalid cell type
-    with pytest.raises(KeyError):
-        pvarray._infer_k_huld_eu_jrc('invalid', pdc0)
+    # Use non-reference values so coefficients affect the result
+    eff_irr = 800  # W/m^2 (not 1000)
+    temp_mod = 35  # deg C (not 25)
+    # Test that EU JRC coefficients give different results than original for all cell types
+    for cell_type in ['cSi', 'CIS', 'CdTe']:
+        res_orig = pvarray.huld(eff_irr, temp_mod, pdc0, cell_type=cell_type)
+        res_eu_jrc = pvarray.huld(eff_irr, temp_mod, pdc0, cell_type=cell_type, use_eu_jrc=True)
+        assert not np.isclose(res_orig, res_eu_jrc), f"Results should differ for {cell_type}: {res_orig} vs {res_eu_jrc}"
+    # Also check that all cell types are supported and error is raised for invalid type
+    try:
+        pvarray.huld(eff_irr, temp_mod, pdc0, cell_type='invalid', use_eu_jrc=True)
+    except KeyError:
+        pass
+    else:
+        assert False, "Expected KeyError for invalid cell_type"