fix: Correctly serialize fee values

mina-p2p-messages/src/v2/manual.rs

@@ -1113,19 +1113,9 @@ impl Serialize for CurrencyFeeStableV1 {
         if remainder == 0 {
             serializer.serialize_str(&whole.to_string())
         } else {
-            let num_stripped_zeros = remainder
-                .to_string()
-                .chars()
-                .rev()
-                .take_while(|&c| c == '0')
-                .count();
-            let num = remainder / 10u64.pow(num_stripped_zeros as u32);
-            serializer.serialize_str(&format!(
-                "{}.{}{}",
-                whole,
-                "0".repeat(PRECISION - num_stripped_zeros),
-                num
-            ))
+            let tmp = format!("{:0width$}", remainder, width = PRECISION);
+            let fractional_str = tmp.trim_end_matches('0');
+            serializer.serialize_str(&format!("{}.{}", whole, fractional_str))
         }
     }
 }
@@ -1161,6 +1151,127 @@ impl<'de> Deserialize<'de> for CurrencyFeeStableV1 {
     }
 }
 
+#[cfg(test)]
+mod tests_currency_fee_serialization {
+    use super::*;
+    use serde_json;
+
+    #[test]
+    fn test_correct_serialization() {
+        let amount = 1_000_000u64;
+        let currency = CurrencyFeeStableV1(amount.into());
+
+        let serialized = serde_json::to_string(&currency).unwrap();
+        assert_eq!(serialized, "\"0.001\"", "Serialization output is incorrect");
+    }
+
+    #[test]
+    fn test_zero_remainder() {
+        let amount = 1_000_000_000u64;
+        let currency = CurrencyFeeStableV1(amount.into());
+
+        let serialized = serde_json::to_string(&currency).unwrap();
+        assert_eq!(
+            serialized, "\"1\"",
+            "Serialization output is incorrect for whole numbers"
+        );
+    }
+
+    #[test]
+    fn test_fractional_serialization() {
+        let amount = 1_234_567_890u64;
+        let currency = CurrencyFeeStableV1(amount.into());
+
+        let serialized = serde_json::to_string(&currency).unwrap();
+        assert_eq!(
+            serialized, "\"1.23456789\"",
+            "Serialization output is incorrect for fractional numbers"
+        );
+    }
+
+    #[test]
+    fn test_trailing_zeros() {
+        let amount = 1_230_000_000u64;
+        let currency = CurrencyFeeStableV1(amount.into());
+
+        let serialized = serde_json::to_string(&currency).unwrap();
+        assert_eq!(
+            serialized, "\"1.23\"",
+            "Serialization output is incorrect when fractional part has trailing zeros"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_correct_serialization() {
+        let serialized = "\"0.001\"";
+        let currency: CurrencyFeeStableV1 = serde_json::from_str(serialized).unwrap();
+        let expected_amount = 1_000_000u64;
+        assert_eq!(
+            currency,
+            CurrencyFeeStableV1(expected_amount.into()),
+            "Deserialization output is incorrect"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_zero_remainder() {
+        let serialized = "\"1\"";
+        let currency: CurrencyFeeStableV1 = serde_json::from_str(serialized).unwrap();
+        let expected_amount = 1_000_000_000u64;
+        assert_eq!(
+            currency,
+            CurrencyFeeStableV1(expected_amount.into()),
+            "Deserialization output is incorrect for whole numbers"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_fractional() {
+        let serialized = "\"1.23456789\"";
+        let currency: CurrencyFeeStableV1 = serde_json::from_str(serialized).unwrap();
+        let expected_amount = 1_234_567_890u64;
+        assert_eq!(
+            currency,
+            CurrencyFeeStableV1(expected_amount.into()),
+            "Deserialization output is incorrect for fractional numbers"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_trailing_zeros() {
+        let serialized = "\"1.23\"";
+        let currency: CurrencyFeeStableV1 = serde_json::from_str(serialized).unwrap();
+        let expected_amount = 1_230_000_000u64;
+        assert_eq!(
+            currency,
+            CurrencyFeeStableV1(expected_amount.into()),
+            "Deserialization output is incorrect when fractional part has trailing zeros"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_truncates_extra_decimals() {
+        let serialized = "\"0.1234567890123\""; // 13 decimal places
+        let currency: CurrencyFeeStableV1 = serde_json::from_str(serialized).unwrap();
+        let expected_amount = 123_456_789u64; // Only the first 9 decimal places are considered
+        assert_eq!(
+            currency,
+            CurrencyFeeStableV1(expected_amount.into()),
+            "Deserialization did not correctly truncate extra decimal places"
+        );
+    }
+
+    #[test]
+    fn test_deserialization_invalid_number() {
+        let serialized = "\"abc\"";
+        let result: Result<CurrencyFeeStableV1, _> = serde_json::from_str(serialized);
+        assert!(
+            result.is_err(),
+            "Deserialization should fail for invalid number strings"
+        );
+    }
+}
+
 #[cfg(test)]
 mod tests_sgn {
     use crate::v2::SgnStableV1;