MAINT: Update test_cross.py to avoid a warning from numpy.cross in Nu…

…mPy 2.0

ufunclab/tests/test_cross.py

@@ -6,6 +6,23 @@
 from ufunclab import cross3, cross2
 
 
+# In numpy 2.0, the handling of length-2 vectors in np.cross
+# is deprecated.  To avoid the deprecation warning, this function
+# is used as a wrapper of np.cross.  This wrapper does not provide
+# the parameter `axisc`.
+def numpy_cross2(a, b, axisa=-1, axisb=-1):
+    a = np.asarray(a)
+    b = np.asarray(b)
+    apad = [(0, 0)]*a.ndim
+    apad[axisa] = (0, 1)
+    bpad = [(0, 0)]*b.ndim
+    bpad[axisb] = (0, 1)
+    a3 = np.pad(a, apad)
+    b3 = np.pad(b, bpad)
+    c = np.cross(a3, b3, axisa=axisa, axisb=axisb)
+    return c[..., -1]
+
+
 @pytest.mark.parametrize('u, v', [([1, 2, 3], [5, 3, 1]),
                                   ([1.5, 0.5, -1.5], [2.0, 9.0, -3.0]),
                                   ([1+2j, 3, -4j], [3-1j, 2j, 6])])
@@ -49,14 +66,14 @@ def test_cross3_nontrivial_axes():
                                   ([1+2j, 3], [3-1j, 2j])])
 def test_cross2_basic(u, v):
     w = cross2(u, v)
-    assert_equal(w, np.cross(u, v))
+    assert_equal(w, numpy_cross2(u, v))
 
 
 def test_cross2_broadcasting():
     x = np.arange(70).reshape(7, 2, 5)
     y = np.arange(10).reshape(5, 2)
     z = cross2(x, y, axes=[(1,), (1,)])
-    assert_equal(z, np.cross(x, y, axisa=1, axisb=1))
+    assert_equal(z, numpy_cross2(x, y, axisa=1, axisb=1))
 
 
 def test_cross2_object():