diff --git a/src/bytes_mut.rs b/src/bytes_mut.rs
index 8783ae7f3..5566f2d1a 100644
--- a/src/bytes_mut.rs
+++ b/src/bytes_mut.rs
@@ -1409,56 +1409,59 @@ fn original_capacity_from_repr(repr: usize) -> usize {
     1 << (repr + (MIN_ORIGINAL_CAPACITY_WIDTH - 1))
 }
 
-/*
-#[test]
-fn test_original_capacity_to_repr() {
-    assert_eq!(original_capacity_to_repr(0), 0);
+#[cfg(test)]
+mod tests {
+    use super::*;
 
-    let max_width = 32;
+    #[test]
+    fn test_original_capacity_to_repr() {
+        assert_eq!(original_capacity_to_repr(0), 0);
 
-    for width in 1..(max_width + 1) {
-        let cap = 1 << width - 1;
+        let max_width = 32;
 
-        let expected = if width < MIN_ORIGINAL_CAPACITY_WIDTH {
-            0
-        } else if width < MAX_ORIGINAL_CAPACITY_WIDTH {
-            width - MIN_ORIGINAL_CAPACITY_WIDTH
-        } else {
-            MAX_ORIGINAL_CAPACITY_WIDTH - MIN_ORIGINAL_CAPACITY_WIDTH
-        };
+        for width in 1..(max_width + 1) {
+            let cap = 1 << width - 1;
 
-        assert_eq!(original_capacity_to_repr(cap), expected);
+            let expected = if width < MIN_ORIGINAL_CAPACITY_WIDTH {
+                0
+            } else if width < MAX_ORIGINAL_CAPACITY_WIDTH {
+                width - MIN_ORIGINAL_CAPACITY_WIDTH
+            } else {
+                MAX_ORIGINAL_CAPACITY_WIDTH - MIN_ORIGINAL_CAPACITY_WIDTH
+            };
 
-        if width > 1 {
-            assert_eq!(original_capacity_to_repr(cap + 1), expected);
-        }
+            assert_eq!(original_capacity_to_repr(cap), expected);
 
-        //  MIN_ORIGINAL_CAPACITY_WIDTH must be bigger than 7 to pass tests below
-        if width == MIN_ORIGINAL_CAPACITY_WIDTH + 1 {
-            assert_eq!(original_capacity_to_repr(cap - 24), expected - 1);
-            assert_eq!(original_capacity_to_repr(cap + 76), expected);
-        } else if width == MIN_ORIGINAL_CAPACITY_WIDTH + 2 {
-            assert_eq!(original_capacity_to_repr(cap - 1), expected - 1);
-            assert_eq!(original_capacity_to_repr(cap - 48), expected - 1);
+            if width > 1 {
+                assert_eq!(original_capacity_to_repr(cap + 1), expected);
+            }
+
+            //  MIN_ORIGINAL_CAPACITY_WIDTH must be bigger than 7 to pass tests below
+            if width == MIN_ORIGINAL_CAPACITY_WIDTH + 1 {
+                assert_eq!(original_capacity_to_repr(cap - 24), expected - 1);
+                assert_eq!(original_capacity_to_repr(cap + 76), expected);
+            } else if width == MIN_ORIGINAL_CAPACITY_WIDTH + 2 {
+                assert_eq!(original_capacity_to_repr(cap - 1), expected - 1);
+                assert_eq!(original_capacity_to_repr(cap - 48), expected - 1);
+            }
         }
     }
-}
 
-#[test]
-fn test_original_capacity_from_repr() {
-    assert_eq!(0, original_capacity_from_repr(0));
+    #[test]
+    fn test_original_capacity_from_repr() {
+        assert_eq!(0, original_capacity_from_repr(0));
 
-    let min_cap = 1 << MIN_ORIGINAL_CAPACITY_WIDTH;
+        let min_cap = 1 << MIN_ORIGINAL_CAPACITY_WIDTH;
 
-    assert_eq!(min_cap, original_capacity_from_repr(1));
-    assert_eq!(min_cap * 2, original_capacity_from_repr(2));
-    assert_eq!(min_cap * 4, original_capacity_from_repr(3));
-    assert_eq!(min_cap * 8, original_capacity_from_repr(4));
-    assert_eq!(min_cap * 16, original_capacity_from_repr(5));
-    assert_eq!(min_cap * 32, original_capacity_from_repr(6));
-    assert_eq!(min_cap * 64, original_capacity_from_repr(7));
+        assert_eq!(min_cap, original_capacity_from_repr(1));
+        assert_eq!(min_cap * 2, original_capacity_from_repr(2));
+        assert_eq!(min_cap * 4, original_capacity_from_repr(3));
+        assert_eq!(min_cap * 8, original_capacity_from_repr(4));
+        assert_eq!(min_cap * 16, original_capacity_from_repr(5));
+        assert_eq!(min_cap * 32, original_capacity_from_repr(6));
+        assert_eq!(min_cap * 64, original_capacity_from_repr(7));
+    }
 }
-*/
 
 unsafe impl Send for BytesMut {}
 unsafe impl Sync for BytesMut {}