diff --git a/src/fs/like.rs b/src/fs/like.rs
new file mode 100644
index 0000000..33e859d
--- /dev/null
+++ b/src/fs/like.rs
@@ -0,0 +1,12 @@
+use super::Result;
+
+use std::path::{Path, PathBuf};
+
+pub trait FileSystemLike {
+    fn base(&self) -> &Path;
+    fn path_of(&self, path: PathBuf) -> Result<PathBuf>;
+    fn file_write(&self, path: &Path, contents: &str) -> Result<()>;
+    fn file_read_to_string(&self, path: &Path) -> Result<String>;
+    fn path_exists(&self, path: &Path) -> Result<bool>;
+    fn path_is_file(&self, path: &Path) -> Result<bool>;
+}
diff --git a/src/fs/mod.rs b/src/fs/mod.rs
index 56a573f..a030ef9 100644
--- a/src/fs/mod.rs
+++ b/src/fs/mod.rs
@@ -1,7 +1,10 @@
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 
 use derive_more::From;
 
+use crate::fs::like::FileSystemLike;
+
+mod like;
 mod real;
 mod temp;
 
@@ -40,11 +43,3 @@ impl std::ops::Deref for FileSystem {
         }
     }
 }
-pub trait FileSystemLike {
-    fn base(&self) -> &Path;
-    fn path_of(&self, path: PathBuf) -> Result<PathBuf>;
-    fn file_write(&self, path: &Path, contents: &str) -> Result<()>;
-    fn file_read_to_string(&self, path: &Path) -> Result<String>;
-    fn path_exists(&self, path: &Path) -> Result<bool>;
-    fn path_is_file(&self, path: &Path) -> Result<bool>;
-}