diff --git a/src/collection/album.rs b/src/collection/album.rs
index 40da9a1..5163eb6 100644
--- a/src/collection/album.rs
+++ b/src/collection/album.rs
@@ -5,7 +5,7 @@ use serde::{Deserialize, Serialize};
 use super::track::Track;
 
 // FIXME: check direction of import.
-use super::{Merge, MergeSorted};
+use super::merge::{Merge, MergeSorted};
 
 /// The album identifier.
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq, PartialOrd, Ord, Eq, Hash)]
diff --git a/src/collection/artist.rs b/src/collection/artist.rs
index 2d99592..639577a 100644
--- a/src/collection/artist.rs
+++ b/src/collection/artist.rs
@@ -11,7 +11,7 @@ use uuid::Uuid;
 use super::album::Album;
 
 // FIXME: check direction of import.
-use super::{Merge, MergeSorted};
+use super::merge::{Merge, MergeSorted};
 
 // FIXME: these imports are not acceptable
 use crate::Error;
diff --git a/src/collection/merge.rs b/src/collection/merge.rs
new file mode 100644
index 0000000..8c7a9a4
--- /dev/null
+++ b/src/collection/merge.rs
@@ -0,0 +1,65 @@
+use std::{cmp::Ordering, iter::Peekable};
+
+pub trait Merge {
+    fn merge_in_place(&mut self, other: Self);
+
+    fn merge(mut self, other: Self) -> Self
+    where
+        Self: Sized,
+    {
+        self.merge_in_place(other);
+        self
+    }
+
+    fn merge_vecs<T: Ord + Eq>(this: &mut Vec<T>, mut other: Vec<T>) {
+        this.append(&mut other);
+        this.sort_unstable();
+        this.dedup();
+    }
+}
+
+pub struct MergeSorted<L, R>
+where
+    L: Iterator<Item = R::Item>,
+    R: Iterator,
+{
+    left: Peekable<L>,
+    right: Peekable<R>,
+}
+
+impl<L, R> MergeSorted<L, R>
+where
+    L: Iterator<Item = R::Item>,
+    R: Iterator,
+{
+    pub fn new(left: L, right: R) -> MergeSorted<L, R> {
+        MergeSorted {
+            left: left.peekable(),
+            right: right.peekable(),
+        }
+    }
+}
+
+impl<L, R> Iterator for MergeSorted<L, R>
+where
+    L: Iterator<Item = R::Item>,
+    R: Iterator,
+    L::Item: Ord + Merge,
+{
+    type Item = L::Item;
+
+    fn next(&mut self) -> Option<L::Item> {
+        let which = match (self.left.peek(), self.right.peek()) {
+            (Some(l), Some(r)) => l.cmp(r),
+            (Some(_), None) => Ordering::Less,
+            (None, Some(_)) => Ordering::Greater,
+            (None, None) => return None,
+        };
+
+        match which {
+            Ordering::Less => self.left.next(),
+            Ordering::Equal => Some(self.left.next().unwrap().merge(self.right.next().unwrap())),
+            Ordering::Greater => self.right.next(),
+        }
+    }
+}
diff --git a/src/collection/mod.rs b/src/collection/mod.rs
index b10883d..6f412b5 100644
--- a/src/collection/mod.rs
+++ b/src/collection/mod.rs
@@ -2,72 +2,8 @@ pub mod album;
 pub mod artist;
 pub mod track;
 
-use std::{cmp::Ordering, iter::Peekable};
-
-// FIXME: should not be public
-pub trait Merge {
-    fn merge_in_place(&mut self, other: Self);
-
-    fn merge(mut self, other: Self) -> Self
-    where
-        Self: Sized,
-    {
-        self.merge_in_place(other);
-        self
-    }
-
-    fn merge_vecs<T: Ord + Eq>(this: &mut Vec<T>, mut other: Vec<T>) {
-        this.append(&mut other);
-        this.sort_unstable();
-        this.dedup();
-    }
-}
-
-struct MergeSorted<L, R>
-where
-    L: Iterator<Item = R::Item>,
-    R: Iterator,
-{
-    left: Peekable<L>,
-    right: Peekable<R>,
-}
-
-impl<L, R> MergeSorted<L, R>
-where
-    L: Iterator<Item = R::Item>,
-    R: Iterator,
-{
-    fn new(left: L, right: R) -> MergeSorted<L, R> {
-        MergeSorted {
-            left: left.peekable(),
-            right: right.peekable(),
-        }
-    }
-}
-
-impl<L, R> Iterator for MergeSorted<L, R>
-where
-    L: Iterator<Item = R::Item>,
-    R: Iterator,
-    L::Item: Ord + Merge,
-{
-    type Item = L::Item;
-
-    fn next(&mut self) -> Option<L::Item> {
-        let which = match (self.left.peek(), self.right.peek()) {
-            (Some(l), Some(r)) => l.cmp(r),
-            (Some(_), None) => Ordering::Less,
-            (None, Some(_)) => Ordering::Greater,
-            (None, None) => return None,
-        };
-
-        match which {
-            Ordering::Less => self.left.next(),
-            Ordering::Equal => Some(self.left.next().unwrap().merge(self.right.next().unwrap())),
-            Ordering::Greater => self.right.next(),
-        }
-    }
-}
+mod merge;
+pub use merge::Merge;
 
 /// The collection alias type for convenience.
 pub type Collection = Vec<artist::Artist>;
diff --git a/src/collection/track.rs b/src/collection/track.rs
index f4279fd..f0510c2 100644
--- a/src/collection/track.rs
+++ b/src/collection/track.rs
@@ -1,7 +1,7 @@
 use serde::{Deserialize, Serialize};
 
 // FIXME: check direction of import.
-use super::Merge;
+use super::merge::Merge;
 
 /// The track file format.
 #[derive(Clone, Copy, Debug, Deserialize, Serialize, PartialEq, Eq, Hash)]