Incorrect serialization of bytes?

[berkowski]

I'm extending serde-json-core for an embedded project to support pretty-formatted serialized strings, tuple variants, and struct variants. It's passing all of the existing tests, except for ser::tests::test_serialize_bytes:

# (Again, my code, not a test error with serde-json-core as-is)
thread 'ser::tests::test_serialize_bytes' panicked at 'assertion failed: `(left == right)`
  left: `"[49,46,53,54]"`,
 right: `"1.56"`', src/ser/mod.rs:1996:9

The current method in ser::Serializer just extends the underlying byte buffer:

    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok> {
        self.extend_from_slice(v)
    }

while the Serde guide serialize_bytes should produce an array:

    // Serialize a byte array as an array of bytes. Could also use a base64
    // string here. Binary formats will typically represent byte arrays more
    // compactly.
    fn serialize_bytes(self, v: &[u8]) -> Result<()> {
        use serde::ser::SerializeSeq;
        let mut seq = self.serialize_seq(Some(v.len()))?;
        for byte in v {
            seq.serialize_element(byte)?;
        }
        seq.end()
    }

serde-json also produces a sequence of bytes. It seems like the test_serialize_bytes test shouldn't be passing as it is currently in serde-json-core. Am I missing something about the implementation specific to serde-json-core?