TEST: Add test that Some(ArrayVec<[&_;_]>).is_some()

This seems like a trivial test, but since it can fail, it shows us that
we don't have a sound implementation yet.

tests/tests.rs

@@ -164,6 +164,14 @@ fn test_compact_size() {
     assert!(mem::size_of::<QuadArray>() <= 24);
 }
 
+#[test]
+fn test_still_works_with_option_arrayvec() {
+    type RefArray = ArrayVec<[&'static i32; 2]>;
+    let array = Some(RefArray::new());
+    assert!(array.is_some());
+    println!("{:?}", array);
+}
+
 #[test]
 fn test_drain() {
     let mut v = ArrayVec::from([0; 8]);