diff --git a/src/lib.rs b/src/lib.rs
index a2b0703..5486e53 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,5 +3,6 @@ pub mod cadence;
 pub mod config;
 pub mod middleware;
 
+#[cfg(test)]
 mod testutils;
 pub mod types;
diff --git a/src/types.rs b/src/types.rs
index 91f33a6..cc3285d 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -40,7 +40,7 @@ pub struct MetricTag<'a> {
 }
 
 impl MetricTag<'_> {
-    pub fn new(bytes: &[u8]) -> MetricTag {
+    pub fn new(bytes: &[u8]) -> MetricTag<'_> {
         MetricTag {
             raw: bytes,
             name_value_sep_pos: bytes.iter().position(|&b| b == b':'),
@@ -135,7 +135,7 @@ impl Metric {
         self.tags_pos.map(|(i, j)| &self.raw[i..j])
     }
 
-    pub fn tags_iter(&self) -> MetricTagIterator {
+    pub fn tags_iter(&self) -> MetricTagIterator<'_> {
         MetricTagIterator {
             remaining_tags: self.tags(),
         }