[vm] Added delta op tests

types/Cargo.toml

@@ -36,6 +36,7 @@ aptos-crypto-derive = { path = "../crates/aptos-crypto-derive" }
 move-deps = { path = "../aptos-move/move-deps", features = ["address32"] }
 
 [dev-dependencies]
+claim = "0.5.0"
 proptest = "1.0.0"
 proptest-derive = "0.3.0"
 regex = "1.5.5"

types/src/delta_set.rs

@@ -66,3 +66,37 @@ pub fn serialize(value: &u128) -> Vec<u8> {
 pub fn deserialize(value_bytes: &Vec<u8>) -> u128 {
     bcs::from_bytes(value_bytes).expect("unexpected deserialization error")
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use claim::{assert_matches, assert_some_eq};
+
+    fn addition(value: u128, limit: u128) -> DeltaOperation {
+        DeltaOperation::Addition { value, limit }
+    }
+
+    fn subtraction(value: u128) -> DeltaOperation {
+        DeltaOperation::Subtraction { value }
+    }
+
+    #[test]
+    fn test_delta_addition() {
+        let add5 = addition(5, 100);
+        assert_some_eq!(add5.apply_to(0), 5);
+        assert_some_eq!(add5.apply_to(5), 10);
+        assert_some_eq!(add5.apply_to(95), 100);
+
+        assert_matches!(add5.apply_to(96), None);
+    }
+
+    #[test]
+    fn test_delta_subtraction() {
+        let sub5 = subtraction(5);
+        assert_matches!(sub5.apply_to(0), None);
+        assert_matches!(sub5.apply_to(1), None);
+
+        assert_some_eq!(sub5.apply_to(5), 0);
+        assert_some_eq!(sub5.apply_to(100), 95);
+    }
+}