diff --git a/justfile b/justfile
index e01dfe3..a6a5136 100644
--- a/justfile
+++ b/justfile
@@ -1,7 +1,8 @@
 build:
+  cargo fmt --check
+  cargo hack --feature-powerset clippy
   cargo hack --feature-powerset build
   cargo hack --feature-powerset test
-  cargo hack --feature-powerset clippy
 
 install-hooks:
   @echo "Installing git hooks"
diff --git a/src/fs/real.rs b/src/fs/real.rs
deleted file mode 100644
index 710a2e1..0000000
--- a/src/fs/real.rs
+++ /dev/null
@@ -1,246 +0,0 @@
-use std::{
-    fmt::Display,
-    path::{Path, PathBuf},
-};
-
-use crate::fs::DirItem;
-
-use super::{DirItemIterator, Result};
-
-#[derive(Clone, Debug)]
-pub struct FileSystem {
-    base: PathBuf,
-}
-impl FileSystem {
-    pub const fn new(base: PathBuf) -> Self {
-        Self { base }
-    }
-    pub fn base(&self) -> &Path {
-        &self.base
-    }
-
-    pub fn path_of(&self, path: PathBuf) -> Result<PathBuf> {
-        let path_of = self.base.as_path().join(path);
-        self.validate(&path_of)?;
-        Ok(path_of)
-    }
-
-    pub fn dir<'base, 'path>(&'base self, path: &'path Path) -> DirReal<'base, 'path> {
-        DirReal::new(self.base(), path)
-    }
-
-    pub fn file<'base, 'path>(&'base self, path: &'path Path) -> FileReal<'base, 'path> {
-        FileReal::new(self.base(), path)
-    }
-
-    pub fn path<'base, 'path>(&'base self, path: &'path Path) -> PathReal<'base, 'path> {
-        PathReal::new(self.base(), path)
-    }
-
-    fn validate(&self, path: &Path) -> Result<()> {
-        let path = self.clean_path(path)?;
-        if !path.starts_with(&self.base) {
-            return Err(super::Error::PathTraversal {
-                base: self.base.clone(),
-                path,
-            });
-        }
-        Ok(())
-    }
-
-    fn clean_path(&self, path: &Path) -> Result<PathBuf> {
-        // let path = path.as_ref();
-        use path_clean::PathClean;
-        let abs_path = if path.is_absolute() {
-            path.to_path_buf()
-        } else {
-            std::env::current_dir()?.join(path)
-        }
-        .clean();
-        Ok(abs_path)
-    }
-}
-
-pub struct DirReal<'base, 'path> {
-    path: PathReal<'base, 'path>,
-}
-impl<'base, 'path> DirReal<'base, 'path> {
-    fn new(base: &'base Path, path: &'path Path) -> Self {
-        let mut path = PathReal::new(base, path);
-        if path.error.is_none() {
-            if let Ok(exists) = path.exists() {
-                if exists {
-                    if let Ok(is_dir) = path.is_dir() {
-                        if !is_dir {
-                            path.put(super::Error::NotADirectory {
-                                path: path.full_path(),
-                            })
-                        }
-                    }
-                }
-            }
-        }
-        Self { path }
-    }
-
-    pub fn create(&mut self) -> Result<()> {
-        self.path.check_error()?;
-        std::fs::create_dir(self.path.full_path()).map_err(Into::into)
-    }
-
-    pub fn create_all(&mut self) -> Result<()> {
-        self.path.check_error()?;
-        std::fs::create_dir_all(self.path.full_path()).map_err(Into::into)
-    }
-
-    pub fn read(&mut self) -> Result<Box<dyn Iterator<Item = Result<DirItem>>>> {
-        self.path.check_error()?;
-        let read_dir = std::fs::read_dir(self.path.full_path())?;
-        Ok(Box::new(DirItemIterator::new(read_dir)))
-    }
-
-    pub fn exists(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        self.path.exists()
-    }
-
-    pub fn is_dir(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        Ok(true)
-    }
-
-    pub fn is_file(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        Ok(false)
-    }
-}
-pub struct FileReal<'base, 'path> {
-    path: PathReal<'base, 'path>,
-}
-impl<'base, 'path> FileReal<'base, 'path> {
-    fn new(base: &'base Path, path: &'path Path) -> Self {
-        Self {
-            path: PathReal::new(base, path),
-        }
-    }
-
-    pub fn reader(&mut self) -> Result<ReaderReal> {
-        self.path.check_error()?;
-        ReaderReal::new(&self.path.full_path())
-    }
-
-    pub fn write(&mut self, contents: &str) -> Result<()> {
-        self.path.check_error()?;
-        std::fs::write(self.path.full_path(), contents).map_err(Into::into)
-    }
-
-    pub fn exists(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        self.path.exists()
-    }
-
-    pub fn is_dir(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        Ok(false)
-    }
-
-    pub fn is_file(&mut self) -> Result<bool> {
-        self.path.check_error()?;
-        Ok(true)
-    }
-}
-#[derive(Debug)]
-pub struct PathReal<'base, 'path> {
-    base: &'base Path,
-    path: &'path Path,
-    error: Option<super::Error>,
-}
-impl<'base, 'path> PathReal<'base, 'path> {
-    fn full_path(&self) -> PathBuf {
-        self.base.join(self.path)
-    }
-    fn put(&mut self, error: super::Error) {
-        if self.error.is_none() {
-            self.error.replace(error);
-        }
-    }
-    fn validate(base: &Path, path: &Path) -> Option<super::Error> {
-        match PathReal::clean_path(path) {
-            Err(error) => Some(error),
-            Ok(path) => {
-                if !path.starts_with(base) {
-                    return Some(super::Error::PathTraversal {
-                        base: base.to_path_buf(),
-                        path,
-                    });
-                }
-                None
-            }
-        }
-    }
-
-    fn clean_path(path: &Path) -> Result<PathBuf> {
-        // let path = path.as_ref();
-        use path_clean::PathClean;
-        let abs_path = if path.is_absolute() {
-            path.to_path_buf()
-        } else {
-            std::env::current_dir().expect("current_dir").join(path)
-        }
-        .clean();
-        Ok(abs_path)
-    }
-
-    fn new(base: &'base Path, path: &'path Path) -> Self {
-        Self {
-            base,
-            path,
-            error: PathReal::validate(base, path),
-        }
-    }
-
-    pub fn exists(&mut self) -> Result<bool> {
-        self.check_error()?;
-        Ok(self.full_path().exists())
-    }
-
-    fn check_error(&mut self) -> Result<()> {
-        if let Some(error) = self.error.take() {
-            return Err(error);
-        }
-        Ok(())
-    }
-
-    pub fn is_dir(&mut self) -> Result<bool> {
-        self.check_error()?;
-        Ok(self.full_path().is_dir())
-    }
-
-    pub fn is_file(&mut self) -> Result<bool> {
-        self.check_error()?;
-        Ok(self.full_path().is_file())
-    }
-}
-impl From<PathReal<'_, '_>> for PathBuf {
-    fn from(path: PathReal) -> Self {
-        path.base.join(path.path)
-    }
-}
-pub struct ReaderReal {
-    contents: String,
-}
-impl ReaderReal {
-    fn new(path: &Path) -> Result<Self> {
-        let contents = std::fs::read_to_string(path)?;
-        Ok(Self { contents })
-    }
-
-    pub fn as_str(&self) -> &str {
-        &self.contents
-    }
-}
-impl Display for ReaderReal {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.contents)
-    }
-}
diff --git a/src/fs/real/dir.rs b/src/fs/real/dir.rs
new file mode 100644
index 0000000..4a1349c
--- /dev/null
+++ b/src/fs/real/dir.rs
@@ -0,0 +1,60 @@
+//
+use std::path::Path;
+
+use crate::fs::{DirItem, DirItemIterator, Error, Result};
+
+use super::path::PathReal;
+
+pub struct DirReal<'base, 'path> {
+    path: PathReal<'base, 'path>,
+}
+impl<'base, 'path> DirReal<'base, 'path> {
+    pub(super) fn new(base: &'base Path, path: &'path Path) -> Self {
+        let mut path = PathReal::new(base, path);
+        if path.error.is_none() {
+            if let Ok(exists) = path.exists() {
+                if exists {
+                    if let Ok(is_dir) = path.is_dir() {
+                        if !is_dir {
+                            path.put(Error::NotADirectory {
+                                path: path.full_path(),
+                            })
+                        }
+                    }
+                }
+            }
+        }
+        Self { path }
+    }
+
+    pub fn create(&mut self) -> Result<()> {
+        self.path.check_error()?;
+        std::fs::create_dir(self.path.full_path()).map_err(Into::into)
+    }
+
+    pub fn create_all(&mut self) -> Result<()> {
+        self.path.check_error()?;
+        std::fs::create_dir_all(self.path.full_path()).map_err(Into::into)
+    }
+
+    pub fn read(&mut self) -> Result<Box<dyn Iterator<Item = Result<DirItem>>>> {
+        self.path.check_error()?;
+        let read_dir = std::fs::read_dir(self.path.full_path())?;
+        Ok(Box::new(DirItemIterator::new(read_dir)))
+    }
+
+    pub fn exists(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        self.path.exists()
+    }
+
+    pub fn is_dir(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        Ok(true)
+    }
+
+    pub fn is_file(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        Ok(false)
+    }
+}
diff --git a/src/fs/real/file.rs b/src/fs/real/file.rs
new file mode 100644
index 0000000..4aef521
--- /dev/null
+++ b/src/fs/real/file.rs
@@ -0,0 +1,42 @@
+//
+use std::path::Path;
+
+use crate::fs::Result;
+
+use super::{path::PathReal, reader::ReaderReal};
+
+pub struct FileReal<'base, 'path> {
+    path: PathReal<'base, 'path>,
+}
+impl<'base, 'path> FileReal<'base, 'path> {
+    pub(super) fn new(base: &'base Path, path: &'path Path) -> Self {
+        Self {
+            path: PathReal::new(base, path),
+        }
+    }
+
+    pub fn reader(&mut self) -> Result<ReaderReal> {
+        self.path.check_error()?;
+        ReaderReal::new(&self.path.full_path())
+    }
+
+    pub fn write(&mut self, contents: &str) -> Result<()> {
+        self.path.check_error()?;
+        std::fs::write(self.path.full_path(), contents).map_err(Into::into)
+    }
+
+    pub fn exists(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        self.path.exists()
+    }
+
+    pub fn is_dir(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        Ok(false)
+    }
+
+    pub fn is_file(&mut self) -> Result<bool> {
+        self.path.check_error()?;
+        Ok(true)
+    }
+}
diff --git a/src/fs/real/mod.rs b/src/fs/real/mod.rs
new file mode 100644
index 0000000..10408cc
--- /dev/null
+++ b/src/fs/real/mod.rs
@@ -0,0 +1,8 @@
+//
+mod dir;
+mod file;
+mod path;
+mod reader;
+mod system;
+
+pub use system::FileSystem;
diff --git a/src/fs/real/path.rs b/src/fs/real/path.rs
new file mode 100644
index 0000000..94e0438
--- /dev/null
+++ b/src/fs/real/path.rs
@@ -0,0 +1,82 @@
+//
+use std::path::{Path, PathBuf};
+
+use crate::fs::{Error, Result};
+
+#[derive(Debug)]
+pub struct PathReal<'base, 'path> {
+    base: &'base Path,
+    path: &'path Path,
+    pub(super) error: Option<Error>,
+}
+impl<'base, 'path> PathReal<'base, 'path> {
+    pub(super) fn full_path(&self) -> PathBuf {
+        self.base.join(self.path)
+    }
+    pub(super) fn put(&mut self, error: Error) {
+        if self.error.is_none() {
+            self.error.replace(error);
+        }
+    }
+    fn validate(base: &Path, path: &Path) -> Option<Error> {
+        match PathReal::clean_path(path) {
+            Err(error) => Some(error),
+            Ok(path) => {
+                if !path.starts_with(base) {
+                    return Some(Error::PathTraversal {
+                        base: base.to_path_buf(),
+                        path,
+                    });
+                }
+                None
+            }
+        }
+    }
+
+    fn clean_path(path: &Path) -> Result<PathBuf> {
+        // let path = path.as_ref();
+        use path_clean::PathClean;
+        let abs_path = if path.is_absolute() {
+            path.to_path_buf()
+        } else {
+            std::env::current_dir().expect("current_dir").join(path)
+        }
+        .clean();
+        Ok(abs_path)
+    }
+
+    pub(super) fn new(base: &'base Path, path: &'path Path) -> Self {
+        Self {
+            base,
+            path,
+            error: PathReal::validate(base, path),
+        }
+    }
+
+    pub fn exists(&mut self) -> Result<bool> {
+        self.check_error()?;
+        Ok(self.full_path().exists())
+    }
+
+    pub(super) fn check_error(&mut self) -> Result<()> {
+        if let Some(error) = self.error.take() {
+            return Err(error);
+        }
+        Ok(())
+    }
+
+    pub fn is_dir(&mut self) -> Result<bool> {
+        self.check_error()?;
+        Ok(self.full_path().is_dir())
+    }
+
+    pub fn is_file(&mut self) -> Result<bool> {
+        self.check_error()?;
+        Ok(self.full_path().is_file())
+    }
+}
+impl From<PathReal<'_, '_>> for PathBuf {
+    fn from(path: PathReal) -> Self {
+        path.base.join(path.path)
+    }
+}
diff --git a/src/fs/real/reader.rs b/src/fs/real/reader.rs
new file mode 100644
index 0000000..a524edd
--- /dev/null
+++ b/src/fs/real/reader.rs
@@ -0,0 +1,23 @@
+//
+use std::{fmt::Display, path::Path};
+
+use crate::fs::Result;
+
+pub struct ReaderReal {
+    contents: String,
+}
+impl ReaderReal {
+    pub(super) fn new(path: &Path) -> Result<Self> {
+        let contents = std::fs::read_to_string(path)?;
+        Ok(Self { contents })
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.contents
+    }
+}
+impl Display for ReaderReal {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.contents)
+    }
+}
diff --git a/src/fs/real/system.rs b/src/fs/real/system.rs
new file mode 100644
index 0000000..829f1e7
--- /dev/null
+++ b/src/fs/real/system.rs
@@ -0,0 +1,60 @@
+//
+use std::path::{Path, PathBuf};
+
+use crate::fs::{Error, Result};
+
+use super::{dir::DirReal, file::FileReal, path::PathReal};
+
+#[derive(Clone, Debug)]
+pub struct FileSystem {
+    base: PathBuf,
+}
+impl FileSystem {
+    pub const fn new(base: PathBuf) -> Self {
+        Self { base }
+    }
+    pub fn base(&self) -> &Path {
+        &self.base
+    }
+
+    pub fn path_of(&self, path: PathBuf) -> Result<PathBuf> {
+        let path_of = self.base.as_path().join(path);
+        self.validate(&path_of)?;
+        Ok(path_of)
+    }
+
+    pub fn dir<'base, 'path>(&'base self, path: &'path Path) -> DirReal<'base, 'path> {
+        DirReal::new(self.base(), path)
+    }
+
+    pub fn file<'base, 'path>(&'base self, path: &'path Path) -> FileReal<'base, 'path> {
+        FileReal::new(self.base(), path)
+    }
+
+    pub fn path<'base, 'path>(&'base self, path: &'path Path) -> PathReal<'base, 'path> {
+        PathReal::new(self.base(), path)
+    }
+
+    fn validate(&self, path: &Path) -> Result<()> {
+        let path = self.clean_path(path)?;
+        if !path.starts_with(&self.base) {
+            return Err(Error::PathTraversal {
+                base: self.base.clone(),
+                path,
+            });
+        }
+        Ok(())
+    }
+
+    fn clean_path(&self, path: &Path) -> Result<PathBuf> {
+        // let path = path.as_ref();
+        use path_clean::PathClean;
+        let abs_path = if path.is_absolute() {
+            path.to_path_buf()
+        } else {
+            std::env::current_dir()?.join(path)
+        }
+        .clean();
+        Ok(abs_path)
+    }
+}