Add unit tests for varint and ringbuffer

src/ringbuffer.rs

@@ -91,6 +91,8 @@ impl<'a, T, const C: usize> Iterator for RingBufferIterator<'a, T, C> {
 
 #[cfg(test)]
 mod tests {
+    use std::default;
+
     use super::*;
 
     #[test]
@@ -117,4 +119,9 @@ mod tests {
             assert_eq!(*i, *j);
         }
     }
+    #[test]
+    fn default() {
+        let mut rb: RingBuffer<i32, 8> = RingBuffer::default();
+        rb.add(42i32);
+    }
 }

src/varint.rs

@@ -97,6 +97,7 @@ mod tests {
             assert!(write(&mut t, ii).is_ok());
             let mut t2 = t.as_slice();
             assert_eq!(read(&mut t2).unwrap().0, ii);
+            assert_eq!(ii, decode(&t).unwrap().0);
         }
     }
 }