BUG: add test coverage for dirint with array-like inputs GH#2751

Author: Omesh37

docs/sphinx/source/whatsnew/v0.15.2.rst

@@ -14,9 +14,9 @@ Deprecations
 
 Bug fixes
 ~~~~~~~~~
-* Fixed :py:func:`pvlib.irradiance.dirint` raising ``KeyError`` with
-  scalar inputs on pandas >= 2.0. (:pull:`2752`, :issue:`2751`)
-  By :ghuser:`Omesh37`.
+* Added test coverage for :py:func:`pvlib.irradiance.dirint` with
+  ``np.array`` and ``pd.Series`` inputs. 
+  (:issue:`2751`, :pull:`2752`)
 * Corrects a bug in :py:func:`pvlib.temperature.fuentes`. If inputs were
   data type integer, users can expect modeled cell temperature values to
   increase slightly.

pvlib/irradiance.py

@@ -1927,10 +1927,10 @@ def dirint(ghi, solar_zenith, times, pressure=101325., use_delta_kt_prime=True,
 
     Parameters
     ----------
-    ghi : numeric
+    ghi : array-like
         Global horizontal irradiance. See :term:`ghi`. [Wm⁻²]
 
-    solar_zenith : numeric
+    solar_zenith : array-like
         True (not refraction-corrected) solar zenith angles. See
         :term:`solar_zenith`. [°]
 
@@ -1964,7 +1964,7 @@ def dirint(ghi, solar_zenith, times, pressure=101325., use_delta_kt_prime=True,
 
     Returns
     -------
-    dni : numeric or pd.Series
+    dni : pd.Series
         Estimated direct normal irradiance. Returns float if all inputs
         are scalar, pd.Series otherwise. [Wm⁻²]
 
@@ -1983,7 +1983,6 @@ def dirint(ghi, solar_zenith, times, pressure=101325., use_delta_kt_prime=True,
        Global Horizontal to Direct Normal Insolation", Technical Report No.
        SERI/TR-215-3087, Golden, CO: Solar Energy Research Institute, 1987.
     """
-    scalar_input = np.isscalar(solar_zenith)
 
     disc_out = disc(ghi, solar_zenith, times, pressure=pressure,
                     min_cos_zenith=min_cos_zenith, max_zenith=max_zenith)
@@ -2002,8 +2001,6 @@ def dirint(ghi, solar_zenith, times, pressure=101325., use_delta_kt_prime=True,
     # Perez eqn 5
     dni = disc_out['dni'] * dirint_coeffs
 
-    if scalar_input:
-        return float(dni.iloc[0])
     return dni
 
 
@@ -2115,10 +2112,6 @@ def _dirint_bins(times, kt_prime, zenith, w, delta_kt_prime):
     # Ensure scalar inputs are converted to Series so that boolean masks
     # produce a boolean Series rather than a scalar bool.
     # Scalar bools cause KeyError in pandas >= 2.0. GH #XXXX
-    kt_prime = pd.Series(kt_prime, index=times, dtype=float)
-    zenith = pd.Series(zenith, index=times, dtype=float)
-    w = pd.Series(w, index=times, dtype=float)
-    delta_kt_prime = pd.Series(delta_kt_prime, index=times, dtype=float)
 
     # @wholmgren: the following bin assignments use MATLAB's 1-indexing.
     # Later, we'll subtract 1 to conform to Python's 0-indexing.

tests/test_irradiance.py

@@ -1140,34 +1140,29 @@ def test_dirindex_min_cos_zenith_max_zenith():
     assert_series_equal(out, expected)
 
 
-def test_dirint_scalar_inputs():
-    """Scalar numeric inputs return scalar float output. GH #2751"""
+def test_dirint_array_inputs():
+    """np.array inputs work correctly. GH #2751"""
     times = pd.DatetimeIndex(['2023-06-21 12:00'], tz='UTC')
 
-    # scalar int input → should return float (not Series)
+    # np.array input (1-element) -- return pd.Series
     result = irradiance.dirint(
-        ghi=500, solar_zenith=45, times=times
-    )
-    assert np.isscalar(result), "scalar input should return scalar output"
-    assert isinstance(result, float)
-
-    # scalar float with delta_kt_prime disabled → non-NaN value check
-    result = irradiance.dirint(
-        ghi=500.0, solar_zenith=45.0, times=times,
+        ghi=np.array([500.0]),
+        solar_zenith=np.array([45.0]),
+        times=times,
         use_delta_kt_prime=False
     )
-    assert np.isscalar(result)
-    assert isinstance(result, float)
-    assert result > 0  # should be positive DNI
+    assert isinstance(result, pd.Series)
+    assert result.iloc[0] > 0
 
-    # Series input → should still return Series (regression check)
+    # pd.Series input -- return pd.Series
     times2 = pd.date_range('2023-06-21 10:00', periods=3, freq='h', tz='UTC')
-    result_series = irradiance.dirint(
+    result2 = irradiance.dirint(
         ghi=pd.Series([400, 500, 300], index=times2),
         solar_zenith=pd.Series([50, 40, 60], index=times2),
         times=times2
     )
-    assert isinstance(result_series, pd.Series)
+    assert isinstance(result2, pd.Series)
+    assert (result2 >= 0).all()
 
 
 def test_dni():