bcf/record/codec/decoder/chromosome_id: Add tests

noodles-bcf/src/record/codec/decoder/chromosome_id.rs

@@ -6,3 +6,28 @@ pub(crate) fn read_chrom(src: &mut &[u8]) -> io::Result<usize> {
     src.read_i32::<LittleEndian>()
         .and_then(|n| usize::try_from(n).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e)))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_read_chrom() -> io::Result<()> {
+        let mut src = &[0x00, 0x00, 0x00, 0x00][..];
+        assert_eq!(read_chrom(&mut src)?, 0);
+
+        let mut src = &[][..];
+        assert!(matches!(
+            read_chrom(&mut src),
+            Err(e) if e.kind() == io::ErrorKind::UnexpectedEof
+        ));
+
+        let mut src = &[0xff, 0xff, 0xff, 0xff][..];
+        assert!(matches!(
+            read_chrom(&mut src),
+            Err(e) if e.kind() == io::ErrorKind::InvalidData
+        ));
+
+        Ok(())
+    }
+}