more zval cast tests

ivory/src/zend/zval.rs

@@ -204,7 +204,7 @@ impl From<u8> for ZValType {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
 pub enum ArrayKey {
     String(String),
     Int(u64),
@@ -227,7 +227,7 @@ impl_from_array_key!(u16, Int, u64);
 impl_from_array_key!(u8, Int, u64);
 impl_from_array_key!(usize, Int, u64);
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub enum PhpVal {
     Undef,
     Null,

ivory/tests/phpval.rs

@@ -1,6 +1,7 @@
 use maplit::hashmap;
 use pretty_assertions::assert_eq;
 
+use ivory::zend::ZVal;
 use ivory::{ArrayKey, PhpVal};
 
 #[test]
@@ -66,3 +67,25 @@ fn cast_into_php_val() {
         .into()
     );
 }
+
+#[test]
+fn cast_into_php_val_round_trip() {
+    let values: Vec<PhpVal> = vec![
+        1.into(),
+        (0.2).into(),
+        true.into(),
+        false.into(),
+        "foo".to_string().into(),
+    ];
+
+    for original in values {
+        let first_cast: ZVal = original.clone().into();
+        let cast_back: PhpVal = first_cast.as_php_val();
+        assert_eq!(original, cast_back);
+
+        // the first round trip should cast back into the same round trip
+        let second_cast: ZVal = cast_back.into();
+        let cast_back: PhpVal = second_cast.as_php_val();
+        assert_eq!(original, cast_back);
+    }
+}