Add tests for Array::from(_mut)_slice methods (#208)

These are deprecated methods there for legacy compatibility

Author: tarcieri

tests/mod.rs

@@ -189,6 +189,36 @@ fn from_ref() {
     assert_eq!(array[0], n);
 }
 
+#[test]
+#[allow(deprecated)]
+fn from_slice_deprecated() {
+    let slice = &[1, 2];
+    assert_eq!(Array::<u8, U2>::from_slice(slice), slice);
+}
+
+#[test]
+#[allow(deprecated)]
+#[should_panic]
+fn from_slice_deprecated_length_mismatch() {
+    let slice = &[1, 2, 3];
+    Array::<u8, U2>::from_slice(slice);
+}
+
+#[test]
+#[allow(deprecated)]
+fn from_mut_slice_deprecated() {
+    let slice = &mut [1, 2];
+    assert_eq!(Array::<u8, U2>::from_mut_slice(slice), &[1, 2]);
+}
+
+#[test]
+#[allow(deprecated)]
+#[should_panic]
+fn from_mut_slice_deprecated_length_mismatch() {
+    let slice = &mut [1, 2, 3];
+    Array::<u8, U2>::from_mut_slice(slice);
+}
+
 #[test]
 fn from_mut() {
     let mut n = 42u64;