TST: Add test for np.tensordot on 0d arrays (numpy#12152)

Collapsing none of the axes on an array with no axes should be expected to work just fine.

Relates to numpygh-12130

numpy/core/tests/test_numeric.py

@@ -2756,3 +2756,9 @@ def test_zero_dimension(self):
         td = np.tensordot(a, b, (1, 0))
         assert_array_equal(td, np.dot(a, b))
         assert_array_equal(td, np.einsum('ij,jk', a, b))
+
+    def test_zero_dimensional(self):
+        # gh-12130
+        arr_0d = np.array(1)
+        ret = np.tensordot(arr_0d, arr_0d, ([], []))  # contracting no axes is well defined
+        assert_array_equal(ret, arr_0d)