Enhance documentation and test cases for Zip::all()

Author: mneumann

src/zip/mod.rs

@@ -741,6 +741,16 @@ macro_rules! map_impl {
             /// Tests if every element of the iterator matches a predicate.
             ///
             /// Returns `true` if `predicate` evaluates to `true` for all elements.
+            /// Returns `true` if the input arrays are empty.
+            ///
+            /// Example:
+            ///
+            /// ```
+            /// use ndarray::{array, Zip};
+            /// let a = array![1, 2, 3];
+            /// let b = array![1, 4, 9];
+            /// assert!(Zip::from(&a).and(&b).all(|&a, &b| a * a == b));
+            /// ```
             pub fn all<F>(mut self, mut predicate: F) -> bool
                 where F: FnMut($($p::Item),*) -> bool
             {

tests/azip.rs

@@ -276,8 +276,11 @@ fn test_indices_split_1() {
 fn test_zip_all() {
     let a = Array::<f32, _>::zeros(62);
     let b = Array::<f32, _>::ones(62);
+    let mut c = Array::<f32, _>::ones(62);
+    c[5] = 0.0;
     assert_eq!(true, Zip::from(&a).and(&b).all(|&x, &y| x + y == 1.0));
     assert_eq!(false, Zip::from(&a).and(&b).all(|&x, &y| x == y));
+    assert_eq!(false, Zip::from(&a).and(&c).all(|&x, &y| x + y == 1.0));
 }
 
 #[test]