test(covenant): improve test coverage

base_layer/core/src/covenants/arguments.rs

@@ -35,7 +35,7 @@ use crate::{
     covenants::{
         byte_codes,
         covenant::Covenant,
-        decoder::{CovenantDecodeError, CovenentReadExt},
+        decoder::{CovenantDecodeError, CovenantReadExt},
         encoder::CovenentWriteExt,
         error::CovenantError,
         fields::{OutputField, OutputFields},
@@ -238,7 +238,12 @@ impl Display for CovenantArg {
 
 #[cfg(test)]
 mod test {
+    use tari_common_types::types::Commitment;
+    use tari_script::script;
+    use tari_utilities::hex::from_hex;
+
     use super::*;
+    use crate::{covenant, covenants::byte_codes::*};
 
     mod require_x_impl {
         use super::*;
@@ -260,18 +265,18 @@ mod test {
         }
     }
 
-    mod write_to {
-        use tari_common_types::types::Commitment;
-        use tari_script::script;
-        use tari_utilities::hex::from_hex;
-
+    mod write_to_and_read_from {
         use super::*;
-        use crate::{covenant, covenants::byte_codes::*};
 
-        fn test_case(arg: CovenantArg, expected: &[u8]) {
+        fn test_case(argument: CovenantArg, mut data: &[u8]) {
             let mut buf = Vec::new();
-            arg.write_to(&mut buf).unwrap();
-            assert_eq!(buf, expected);
+            argument.write_to(&mut buf).unwrap();
+            assert_eq!(buf, data);
+
+            let reader = &mut data;
+            let code = reader.read_next_byte_code().unwrap().unwrap();
+            let arg = CovenantArg::read_from(&mut data, code).unwrap();
+            assert_eq!(arg, argument);
         }
 
         #[test]

base_layer/core/src/covenants/byte_codes.rs

@@ -22,8 +22,21 @@
 
 //---------------------------------- ARG byte codes --------------------------------------------//
 pub(super) fn is_valid_arg_code(code: u8) -> bool {
-    (0x01..=0x09).contains(&code)
+    ALL_ARGS.contains(&code)
 }
+
+pub(super) const ALL_ARGS: [u8; 9] = [
+    ARG_HASH,
+    ARG_PUBLIC_KEY,
+    ARG_COMMITMENT,
+    ARG_TARI_SCRIPT,
+    ARG_COVENANT,
+    ARG_UINT,
+    ARG_OUTPUT_FIELD,
+    ARG_OUTPUT_FIELDS,
+    ARG_BYTES,
+];
+
 pub const ARG_HASH: u8 = 0x01;
 pub const ARG_PUBLIC_KEY: u8 = 0x02;
 pub const ARG_COMMITMENT: u8 = 0x03;
@@ -37,9 +50,22 @@ pub const ARG_BYTES: u8 = 0x09;
 //---------------------------------- FILTER byte codes --------------------------------------------//
 
 pub(super) fn is_valid_filter_code(code: u8) -> bool {
-    (0x20..=0x24).contains(&code) || (0x30..=0x34).contains(&code)
+    ALL_FILTERS.contains(&code)
 }
 
+pub(super) const ALL_FILTERS: [u8; 10] = [
+    FILTER_IDENTITY,
+    FILTER_AND,
+    FILTER_OR,
+    FILTER_XOR,
+    FILTER_NOT,
+    FILTER_OUTPUT_HASH_EQ,
+    FILTER_FIELDS_PRESERVED,
+    FILTER_FIELDS_HASHED_EQ,
+    FILTER_FIELD_EQ,
+    FILTER_ABSOLUTE_HEIGHT,
+];
+
 pub const FILTER_IDENTITY: u8 = 0x20;
 pub const FILTER_AND: u8 = 0x21;
 pub const FILTER_OR: u8 = 0x22;
@@ -63,3 +89,44 @@ pub const FIELD_FEATURES_MATURITY: u8 = 0x06;
 pub const FIELD_FEATURES_UNIQUE_ID: u8 = 0x07;
 pub const FIELD_FEATURES_PARENT_PUBLIC_KEY: u8 = 0x08;
 pub const FIELD_FEATURES_METADATA: u8 = 0x09;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    mod is_valid_filter_code {
+        use super::*;
+
+        #[test]
+        fn it_returns_true_for_all_filter_codes() {
+            ALL_FILTERS.iter().for_each(|code| {
+                assert!(is_valid_filter_code(*code));
+            });
+        }
+
+        #[test]
+        fn it_returns_false_for_all_arg_codes() {
+            ALL_ARGS.iter().for_each(|code| {
+                assert!(!is_valid_filter_code(*code));
+            });
+        }
+    }
+
+    mod is_valid_arg_code {
+        use super::*;
+
+        #[test]
+        fn it_returns_false_for_all_filter_codes() {
+            ALL_FILTERS.iter().for_each(|code| {
+                assert!(!is_valid_arg_code(*code));
+            });
+        }
+
+        #[test]
+        fn it_returns_true_for_all_arg_codes() {
+            ALL_ARGS.iter().for_each(|code| {
+                assert!(is_valid_arg_code(*code));
+            });
+        }
+    }
+}

base_layer/core/src/covenants/decoder.rs

@@ -81,12 +81,12 @@ pub enum CovenantDecodeError {
     Io(#[from] io::Error),
 }
 
-pub(super) trait CovenentReadExt: io::Read {
+pub(super) trait CovenantReadExt: io::Read {
     fn read_next_byte_code(&mut self) -> Result<Option<u8>, io::Error>;
     fn read_variable_length_bytes(&mut self, size: usize) -> Result<Vec<u8>, io::Error>;
 }
 
-impl<R: io::Read> CovenentReadExt for R {
+impl<R: io::Read> CovenantReadExt for R {
     fn read_next_byte_code(&mut self) -> Result<Option<u8>, io::Error> {
         let mut buf = [0u8; 1];
         loop {
@@ -127,7 +127,12 @@ mod test {
     use super::*;
     use crate::{
         covenant,
-        covenants::{arguments::CovenantArg, fields::OutputField, filters::CovenantFilter},
+        covenants::{
+            arguments::CovenantArg,
+            byte_codes::ARG_OUTPUT_FIELD,
+            fields::OutputField,
+            filters::CovenantFilter,
+        },
     };
 
     #[test]
@@ -136,6 +141,28 @@ mod test {
         assert!(CovenantTokenDecoder::new(&mut &buf[..]).next().is_none());
     }
 
+    #[test]
+    fn it_ends_after_an_error() {
+        let buf = &[0xffu8];
+        let mut reader = &buf[..];
+        let mut decoder = CovenantTokenDecoder::new(&mut reader);
+        assert!(matches!(decoder.next(), Some(Err(_))));
+        assert!(decoder.next().is_none());
+    }
+
+    #[test]
+    fn it_returns_an_error_if_arg_expected() {
+        let buf = &[ARG_OUTPUT_FIELD];
+        let mut reader = &buf[..];
+        let mut decoder = CovenantTokenDecoder::new(&mut reader);
+
+        assert!(matches!(
+            decoder.next(),
+            Some(Err(CovenantDecodeError::UnexpectedEof { .. }))
+        ));
+        assert!(decoder.next().is_none());
+    }
+
     #[test]
     fn it_decodes_from_well_formed_bytes() {
         let hash = from_hex("53563b674ba8e5166adb57afa8355bcf2ee759941eef8f8959b802367c2558bd").unwrap();
@@ -171,4 +198,21 @@ mod test {
 
         assert!(decoder.next().is_none());
     }
+
+    mod covenant_read_ext {
+        use super::*;
+
+        #[test]
+        fn it_reads_bytes_with_length_prefix() {
+            let data = vec![0x03u8, 0x01, 0x02, 0x03];
+            let bytes = CovenantReadExt::read_variable_length_bytes(&mut data.as_slice(), 3).unwrap();
+            assert_eq!(bytes, [1u8, 2, 3]);
+        }
+
+        #[test]
+        fn it_errors_if_len_byte_exceeds_maximum() {
+            let data = vec![0x02, 0x01];
+            CovenantReadExt::read_variable_length_bytes(&mut data.as_slice(), 1).unwrap_err();
+        }
+    }
 }

base_layer/core/src/covenants/encoder.rs

@@ -52,3 +52,63 @@ impl<W: io::Write> CovenentWriteExt for W {
         Ok(1)
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+    use crate::{
+        covenant,
+        covenants::{
+            byte_codes::{ARG_HASH, ARG_OUTPUT_FIELD, FILTER_AND, FILTER_FIELD_EQ, FILTER_IDENTITY, FILTER_OR},
+            OutputField,
+        },
+    };
+
+    #[test]
+    fn it_encodes_empty_tokens() {
+        let encoder = CovenantTokenEncoder::new(&[]);
+        let mut buf = Vec::<u8>::new();
+        let written = encoder.write_to(&mut buf).unwrap();
+        assert_eq!(buf, [] as [u8; 0]);
+        assert_eq!(written, 0);
+    }
+
+    #[test]
+    fn it_encodes_tokens_correctly() {
+        let covenant = covenant!(and(identity(), or(identity())));
+        let encoder = CovenantTokenEncoder::new(covenant.tokens());
+        let mut buf = Vec::<u8>::new();
+        let written = encoder.write_to(&mut buf).unwrap();
+        assert_eq!(buf, [FILTER_AND, FILTER_IDENTITY, FILTER_OR, FILTER_IDENTITY]);
+        assert_eq!(written, 4);
+    }
+
+    #[test]
+    fn it_encodes_args_correctly() {
+        let dummy = [0u8; 32];
+        let covenant = covenant!(field_eq(@field::features, @hash(dummy)));
+        let encoder = CovenantTokenEncoder::new(covenant.tokens());
+        let mut buf = Vec::<u8>::new();
+        let written = encoder.write_to(&mut buf).unwrap();
+        assert_eq!(buf[..4], [
+            FILTER_FIELD_EQ,
+            ARG_OUTPUT_FIELD,
+            OutputField::Features.as_byte(),
+            ARG_HASH
+        ]);
+        assert_eq!(buf[4..], [0u8; 32]);
+        assert_eq!(written, 36);
+    }
+
+    mod covenant_write_ext {
+        use super::*;
+
+        #[test]
+        fn it_writes_a_single_byte() {
+            let mut buf = Vec::new();
+            buf.write_u8_fixed(123u8).unwrap();
+            assert_eq!(buf, vec![123u8]);
+        }
+    }
+}

base_layer/core/src/covenants/error.rs

@@ -40,6 +40,4 @@ pub enum CovenantError {
     RemainingTokens,
     #[error("Invalid argument for filter {filter}: {details}")]
     InvalidArgument { filter: &'static str, details: String },
-    #[error("Unsupported argument {arg}: {details}")]
-    UnsupportedArgument { arg: &'static str, details: String },
 }