diff --git a/src/encoders/mod.rs b/src/encoders/mod.rs
index e69de29bb2..0863ededfa 100644
--- a/src/encoders/mod.rs
+++ b/src/encoders/mod.rs
@@ -0,0 +1 @@
+mod simple8b;
diff --git a/src/encoders/simple8b.rs b/src/encoders/simple8b/mod.rs
similarity index 99%
rename from src/encoders/simple8b.rs
rename to src/encoders/simple8b/mod.rs
index d6cb822690..5bd0ae0da8 100644
--- a/src/encoders/simple8b.rs
+++ b/src/encoders/simple8b/mod.rs
@@ -205,3 +205,6 @@ pub fn decode(v: u64, dst: &mut [u64]) -> usize {
         _ => 0,
     }
 }
+
+#[cfg(test)]
+mod tests;