diff --git a/Cargo.lock b/Cargo.lock
index 6b4f500..f206dad 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,4 +1,114 @@
+[[package]]
+name = "bitflags"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "cloudabi"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "fuchsia-zircon"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "fuchsia-zircon-sys"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "libc"
+version = "0.2.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "rand"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "redox_syscall"
+version = "0.1.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "remove_dir_all"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rustback"
 version = "0.1.0"
+dependencies = [
+ "tempfile 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
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+name = "tempfile"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
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+ "redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
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+name = "winapi"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
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+ "winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
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diff --git a/Cargo.toml b/Cargo.toml
index 3f15d21..2d2f48f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,3 +4,6 @@ version = "0.1.0"
 authors = ["Cyryl Płotnicki <cyplo@cyplo.net>"]
 
 [dependencies]
+
+[dev-dependencies]
+tempfile = "3.0.3"
diff --git a/src/main.rs b/src/main.rs
index 22925b7..8edc3df 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,47 @@
+extern crate tempfile;
 
+mod rustback {
+
+    use super::*;
+
+    #[cfg(test)]
+    mod should {
+
+        use super::*;
+        use tempfile::tempdir;
+        use std::fs::File;
+        use std::io::{self, Write};
+        use std::io::Error;
+
+        #[test]
+        fn be_able_to_restore_backed_up_files() -> Result<(), Error> {
+
+            let dir = tempdir()?;
+
+            let file_path = dir.path().join("my-temporary-note.txt");
+            let mut file = File::create(file_path)?;
+            writeln!(file, "Brian was here. Briefly.")?;
+
+            // create a new temp folder
+            // add 3 files, two identical content
+            // remember file hashes
+            let source_path = dir.path();
+
+            //create a new temp folder
+            let destination_path = "";
+            //let walker = FilesystemWalker::new(source_path);
+            //let engine = Engine::with(walker);
+
+            //engine.backup();
+            //engine.restore(destination_path);
+
+            // assert on number and hashes of files
+            Ok(())
+        }
+
+    }
+
+}
 
 mod index {
     use super::*;
@@ -8,18 +51,7 @@ mod index {
 
         #[test]
         fn recognize_files_of_same_contents() {
-            let file_source = FileSource::new();
-
-            file_source.add("file name 1", "file contents 1");
-            file_source.add("file name 2", "file contents 1");
-            file_source.add("file name 3", "file contents 3");
-
-            let contents_hasher = FakeContentsHasher::default();
-            
-
-            let index = Index::with(file_source, contents_hasher);
-
-
+            assert!(false);
         }
 
     }