diff --git a/jobs-sled/src/error.rs b/jobs-sled/src/error.rs
new file mode 100644
index 0000000..d320058
--- /dev/null
+++ b/jobs-sled/src/error.rs
@@ -0,0 +1,21 @@
+use failure::Fail;
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Clone, Debug, Fail)]
+pub enum Error {
+    #[fail(display = "Error in database: {}", _0)]
+    Sled(#[cause] sled::Error),
+
+    #[fail(display = "Failed to deserialize data")]
+    Deserialize,
+
+    #[fail(display = "Failed to serialize data")]
+    Serialize,
+}
+
+impl From<sled::Error> for Error {
+    fn from(e: sled::Error) -> Self {
+        Error::Sled(e)
+    }
+}
diff --git a/jobs-sled/src/lib.rs b/jobs-sled/src/lib.rs
index e121781..183a66f 100644
--- a/jobs-sled/src/lib.rs
+++ b/jobs-sled/src/lib.rs
@@ -1,6 +1,14 @@
 use background_jobs_core::{JobInfo, Storage, Stats};
-use failure::Fail;
-use std::{marker::PhantomData, sync::Arc};
+
+mod error;
+mod sled_wrappers;
+
+pub use error::Error;
+
+use self::{
+    error::Result,
+    sled_wrappers::Tree,
+};
 
 #[derive(Clone)]
 pub struct SledStorage {
@@ -88,14 +96,6 @@ impl Storage for SledStorage {
     }
 }
 
-fn job_key(id: u64) -> String {
-    format!("job-{}", id)
-}
-
-fn runner_key(runner_id: u64) -> String {
-    format!("runner-{}", runner_id)
-}
-
 impl SledStorage {
     pub fn new(db: sled::Db) -> Result<Self> {
         Ok(SledStorage {
@@ -109,6 +109,14 @@ impl SledStorage {
     }
 }
 
+fn job_key(id: u64) -> String {
+    format!("job-{}", id)
+}
+
+fn runner_key(runner_id: u64) -> String {
+    format!("runner-{}", runner_id)
+}
+
 fn open_tree<T>(db: &sled::Db, name: &str) -> sled::Result<Tree<T>>
 where
     T: serde::de::DeserializeOwned + serde::ser::Serialize,
@@ -116,144 +124,3 @@ where
     db.open_tree(name).map(Tree::new)
 }
 
-
-#[derive(Clone)]
-struct Tree<T>(Arc<sled::Tree>, PhantomData<T>);
-
-impl<T> Tree<T>
-where
-    T: serde::de::DeserializeOwned + serde::ser::Serialize,
-{
-    fn new(t: Arc<sled::Tree>) -> Self {
-        Tree(t, PhantomData)
-    }
-
-    fn iter(&self) -> Iter<T> {
-        Iter::new(self.0.iter())
-    }
-
-    fn get<K>(&self, key: K) -> Result<Option<T>>
-    where
-        K: AsRef<[u8]>
-    {
-        match self.0.get(key)? {
-            Some(vec) => {
-                serde_json::from_slice(&vec)
-                    .map_err(|_| Error::Deserialize)
-                    .map(Some)
-            },
-            None => Ok(None),
-        }
-    }
-
-    fn set(&self, key: &str, value: T) -> Result<Option<T>> {
-        let vec = serde_json::to_vec(&value).map_err(|_| Error::Serialize)?;
-
-        Ok(self.0.set(key, vec)?.map(move |_| value))
-    }
-
-    fn del(&self, key: &str) -> Result<Option<T>> {
-        match self.0.del(key)? {
-            Some(vec) => {
-                serde_json::from_slice(&vec)
-                    .map_err(|_| Error::Deserialize)
-                    .map(Some)
-            },
-            None => Ok(None),
-        }
-    }
-
-    fn fetch_and_update<F>(&self, key: &str, f: F) -> Result<Option<T>>
-    where
-        F: Fn(Option<T>) -> Option<T>,
-    {
-        let final_opt = self.0.fetch_and_update(key, |opt| {
-            let new_opt = match opt {
-                Some(vec) => {
-                    let t = serde_json::from_slice(&vec)
-                        .map(Some)
-                        .unwrap_or(None);
-
-                    (f)(t)
-                },
-                None => (f)(None),
-            };
-
-            match new_opt {
-                Some(t) => serde_json::to_vec(&t)
-                    .map(Some)
-                    .unwrap_or(None),
-                None => None,
-            }
-        })?;
-
-        match final_opt {
-            Some(vec) => {
-                serde_json::from_slice(&vec)
-                    .map_err(|_| Error::Deserialize)
-                    .map(Some)
-            },
-            None => Ok(None),
-        }
-    }
-}
-
-struct Iter<'a, T>(sled::Iter<'a>, PhantomData<T>);
-
-impl<'a, T> Iter<'a, T> {
-    fn new(i: sled::Iter<'a>) -> Self {
-        Iter(i, PhantomData)
-    }
-}
-
-#[derive(Clone, Debug, Fail)]
-pub enum Error {
-    #[fail(display = "Error in database: {}", _0)]
-    Sled(#[cause] sled::Error),
-
-    #[fail(display = "Failed to deserialize data")]
-    Deserialize,
-
-    #[fail(display = "Failed to serialize data")]
-    Serialize,
-}
-
-type Result<T> = std::result::Result<T, Error>;
-
-impl<'a, T> Iterator for Iter<'a, T>
-where
-    T: serde::de::DeserializeOwned
-{
-    type Item = Result<(Vec<u8>, T)>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.0.next().map(|res| {
-            res.map_err(Error::from).and_then(|(k, v)| {
-                serde_json::from_slice(&v)
-                    .map(|item| (k, item))
-                    .map_err(|_| Error::Deserialize)
-            })
-        })
-    }
-}
-
-impl<'a, T> DoubleEndedIterator for Iter<'a, T>
-where
-    T: serde::de::DeserializeOwned
-{
-    fn next_back(&mut self) -> Option<Self::Item> {
-        self.0.next_back().map(|res| {
-            res.map_err(Error::from).and_then(|(k, v)| {
-                serde_json::from_slice(&v)
-                    .map(|item| (k, item))
-                    .map_err(|_| Error::Deserialize)
-            })
-        })
-    }
-}
-
-impl From<sled::Error> for Error {
-    fn from(e: sled::Error) -> Self {
-        Error::Sled(e)
-    }
-}
diff --git a/jobs-sled/src/sled_wrappers.rs b/jobs-sled/src/sled_wrappers.rs
new file mode 100644
index 0000000..e3190a4
--- /dev/null
+++ b/jobs-sled/src/sled_wrappers.rs
@@ -0,0 +1,124 @@
+use std::{marker::PhantomData, sync::Arc};
+
+use crate::{Error, Result};
+
+#[derive(Clone)]
+pub struct Tree<T>(Arc<sled::Tree>, PhantomData<T>);
+
+impl<T> Tree<T>
+where
+    T: serde::de::DeserializeOwned + serde::ser::Serialize,
+{
+    pub(crate) fn new(t: Arc<sled::Tree>) -> Self {
+        Tree(t, PhantomData)
+    }
+
+    pub(crate) fn iter(&self) -> Iter<T> {
+        Iter::new(self.0.iter())
+    }
+
+    pub(crate) fn get<K>(&self, key: K) -> Result<Option<T>>
+    where
+        K: AsRef<[u8]>
+    {
+        match self.0.get(key)? {
+            Some(vec) => {
+                serde_json::from_slice(&vec)
+                    .map_err(|_| Error::Deserialize)
+                    .map(Some)
+            },
+            None => Ok(None),
+        }
+    }
+
+    pub(crate) fn set(&self, key: &str, value: T) -> Result<Option<T>> {
+        let vec = serde_json::to_vec(&value).map_err(|_| Error::Serialize)?;
+
+        Ok(self.0.set(key, vec)?.map(move |_| value))
+    }
+
+    pub(crate) fn del(&self, key: &str) -> Result<Option<T>> {
+        match self.0.del(key)? {
+            Some(vec) => {
+                serde_json::from_slice(&vec)
+                    .map_err(|_| Error::Deserialize)
+                    .map(Some)
+            },
+            None => Ok(None),
+        }
+    }
+
+    pub(crate) fn fetch_and_update<F>(&self, key: &str, f: F) -> Result<Option<T>>
+    where
+        F: Fn(Option<T>) -> Option<T>,
+    {
+        let final_opt = self.0.fetch_and_update(key, |opt| {
+            let new_opt = match opt {
+                Some(vec) => {
+                    let t = serde_json::from_slice(&vec)
+                        .map(Some)
+                        .unwrap_or(None);
+
+                    (f)(t)
+                },
+                None => (f)(None),
+            };
+
+            match new_opt {
+                Some(t) => serde_json::to_vec(&t)
+                    .map(Some)
+                    .unwrap_or(None),
+                None => None,
+            }
+        })?;
+
+        match final_opt {
+            Some(vec) => {
+                serde_json::from_slice(&vec)
+                    .map_err(|_| Error::Deserialize)
+                    .map(Some)
+            },
+            None => Ok(None),
+        }
+    }
+}
+
+pub(crate) struct Iter<'a, T>(sled::Iter<'a>, PhantomData<T>);
+
+impl<'a, T> Iter<'a, T> {
+    fn new(i: sled::Iter<'a>) -> Self {
+        Iter(i, PhantomData)
+    }
+}
+
+impl<'a, T> Iterator for Iter<'a, T>
+where
+    T: serde::de::DeserializeOwned
+{
+    type Item = Result<(Vec<u8>, T)>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next().map(|res| {
+            res.map_err(Error::from).and_then(|(k, v)| {
+                serde_json::from_slice(&v)
+                    .map(|item| (k, item))
+                    .map_err(|_| Error::Deserialize)
+            })
+        })
+    }
+}
+
+impl<'a, T> DoubleEndedIterator for Iter<'a, T>
+where
+    T: serde::de::DeserializeOwned
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back().map(|res| {
+            res.map_err(Error::from).and_then(|(k, v)| {
+                serde_json::from_slice(&v)
+                    .map(|item| (k, item))
+                    .map_err(|_| Error::Deserialize)
+            })
+        })
+    }
+}