add tests/mutants.rs

Author: cehteh

tests/mutants.rs

@@ -0,0 +1,19 @@
+use header_vec::HeaderVec;
+#[test]
+fn test_truncate_remaining_len() {
+    let mut vec: HeaderVec<(), i32> = HeaderVec::from([1, 2, 3, 4, 5]);
+    let len = vec.len();
+    vec.truncate(2);
+    assert_eq!(vec.len(), 2);
+    assert_eq!(vec.as_slice(), &[1, 2]);
+    assert!(vec.capacity() >= len);
+}
+
+#[test]
+fn test_drain_size_hint() {
+    let mut vec: HeaderVec<(), i32> = HeaderVec::from([1, 2, 3, 4, 5]);
+    let drain = vec.drain(1..4);
+    let (lower, upper) = drain.size_hint();
+    assert_eq!(lower, 3);
+    assert_eq!(upper, Some(3));
+}