DEP: Make `np.insert` and `np.delete` on 0d arrays with an axis an error

Before this change, the following code worked:

```
>>> some_0d = np.array(1)
>>> np.insert(some_0d, "some nonsense", 10, axis=0)
array(10)
>>> np.insert(some_0d, "some nonsense", 42, axis="some nonsense")
array(42)
```

Now these raise AxisError and TypeError, respectively.

`delete` is exactly the same.

1 files changed, 8 insertions, 9 deletions

diff --git a/numpy/lib/tests/test_function_base.py b/numpy/lib/tests/test_function_base.py
index 860cf452b..65bc9f1ec 100644
--- a/numpy/lib/tests/test_function_base.py
+++ b/numpy/lib/tests/test_function_base.py
@@ -509,12 +509,11 @@ class TestInsert:
                      insert(a, 1, a[:, 2, :], axis=1))
 
     def test_0d(self):
-        # This is an error in the future
         a = np.array(1)
-        with warnings.catch_warnings(record=True) as w:
-            warnings.filterwarnings('always', '', DeprecationWarning)
-            assert_equal(insert(a, [], 2, axis=0), np.array(2))
-            assert_(w[0].category is DeprecationWarning)
+        with pytest.raises(np.AxisError):
+            insert(a, [], 2, axis=0)
+        with pytest.raises(TypeError):
+            insert(a, [], 2, axis="nonsense")
 
     def test_subclass(self):
         class SubClass(np.ndarray):
@@ -843,10 +842,10 @@ class TestDelete:
 
     def test_0d(self):
         a = np.array(1)
-        with warnings.catch_warnings(record=True) as w:
-            warnings.filterwarnings('always', '', DeprecationWarning)
-            assert_equal(delete(a, [], axis=0), a)
-            assert_(w[0].category is DeprecationWarning)
+        with pytest.raises(np.AxisError):
+            delete(a, [], axis=0)
+        with pytest.raises(TypeError):
+            delete(a, [], axis="nonsense")
 
     def test_subclass(self):
         class SubClass(np.ndarray):