From 7699e0cdbf5208a610fb38bc4c7479b45a78fad3 Mon Sep 17 00:00:00 2001
From: bluss <bluss@users.noreply.github.com>
Date: Mon, 22 Mar 2021 19:03:49 +0100
Subject: [PATCH] TEST: Test for negative stride constructors for Raw/ArrayView

---
 src/impl_views/constructors.rs |  1 +
 tests/array.rs                 | 61 ++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/src/impl_views/constructors.rs b/src/impl_views/constructors.rs
index 88a289ce7..fd9457fa1 100644
--- a/src/impl_views/constructors.rs
+++ b/src/impl_views/constructors.rs
@@ -30,6 +30,7 @@ where
     /// use ndarray::arr3;
     /// use ndarray::ShapeBuilder;
     ///
+    /// // advanced example where we are even specifying exact strides to use (which is optional).
     /// let s = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12];
     /// let a = ArrayView::from_shape((2, 3, 2).strides((1, 4, 2)),
     ///                               &s).unwrap();
diff --git a/tests/array.rs b/tests/array.rs
index b1d37da70..8e084e49e 100644
--- a/tests/array.rs
+++ b/tests/array.rs
@@ -1827,6 +1827,27 @@ fn map_memory_order() {
     assert_eq!(amap.strides(), v.strides());
 }
 
+#[test]
+fn test_view_from_shape() {
+    let s = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
+    let a = ArrayView::from_shape((2, 3, 2), &s).unwrap();
+    let mut answer = Array::from(s.to_vec()).into_shape((2, 3, 2)).unwrap();
+    assert_eq!(a, answer);
+
+    // custom strides (row major)
+    let a = ArrayView::from_shape((2, 3, 2).strides((6, 2, 1)), &s).unwrap();
+    assert_eq!(a, answer);
+
+    // custom strides (col major)
+    let a = ArrayView::from_shape((2, 3, 2).strides((1, 2, 6)), &s).unwrap();
+    assert_eq!(a, answer.t());
+
+    // negative strides
+    let a = ArrayView::from_shape((2, 3, 2).strides((6, (-2isize) as usize, 1)), &s).unwrap();
+    answer.invert_axis(Axis(1));
+    assert_eq!(a, answer);
+}
+
 #[test]
 fn test_contiguous() {
     let c = arr3(&[[[1, 2, 3], [4, 5, 6]], [[4, 5, 6], [7, 7, 7]]]);
@@ -1973,6 +1994,46 @@ fn test_view_from_shape_ptr() {
     assert_eq!(view, aview2(&[[0, 0, 2], [3, 4, 6]]));
 }
 
+#[should_panic(expected = "Unsupported")]
+#[cfg(debug_assertions)]
+#[test]
+fn test_view_from_shape_ptr_deny_neg_strides() {
+    let data = [0, 1, 2, 3, 4, 5];
+    let _view = unsafe {
+        ArrayView::from_shape_ptr((2, 3).strides((-3isize as usize, 1)), data.as_ptr())
+    };
+}
+
+#[should_panic(expected = "Unsupported")]
+#[cfg(debug_assertions)]
+#[test]
+fn test_view_mut_from_shape_ptr_deny_neg_strides() {
+    let mut data = [0, 1, 2, 3, 4, 5];
+    let _view = unsafe {
+        ArrayViewMut::from_shape_ptr((2, 3).strides((-3isize as usize, 1)), data.as_mut_ptr())
+    };
+}
+
+#[should_panic(expected = "Unsupported")]
+#[cfg(debug_assertions)]
+#[test]
+fn test_raw_view_from_shape_ptr_deny_neg_strides() {
+    let data = [0, 1, 2, 3, 4, 5];
+    let _view = unsafe {
+        RawArrayView::from_shape_ptr((2, 3).strides((-3isize as usize, 1)), data.as_ptr())
+    };
+}
+
+#[should_panic(expected = "Unsupported")]
+#[cfg(debug_assertions)]
+#[test]
+fn test_raw_view_mut_from_shape_ptr_deny_neg_strides() {
+    let mut data = [0, 1, 2, 3, 4, 5];
+    let _view = unsafe {
+        RawArrayViewMut::from_shape_ptr((2, 3).strides((-3isize as usize, 1)), data.as_mut_ptr())
+    };
+}
+
 #[test]
 fn test_default() {
     let a = <Array<f32, Ix2> as Default>::default();