add test for row_st case to help coverage and test new array interface

Author: dschult

libpysal/weights/tests/test_util.py

@@ -34,8 +34,11 @@ def test_lat2_sw(self, row_st):
         pct_nonzero = w9.nnz / float(n)
         assert pct_nonzero == 0.29629629629629628
         if row_st:
-            # undo normalization to allow easy check: multiply each row by # entries
-            w9 = (w9.T.multiply(w9.count_nonzero(axis=1))).T
+            # these 3 lines can be replaced when scipy >=1.15 is assured.
+            # w9 = (w9.T.multiply(w9.tocsr().count_nonzero(axis=1))).T
+            w9csr = w9.tocsr()
+            nnz_by_axis1 = np.diff(w9csr.indptr)
+            w9 = (w9csr.T.multiply(nnz_by_axis1)).T
         data = w9.todense().tolist()
         assert data[0] == [0, 1, 0, 1, 0, 0, 0, 0, 0]
         assert data[1] == [1, 0, 1, 0, 1, 0, 0, 0, 0]