diff --git a/tests/deduplication_tests.rs b/tests/deduplication_tests.rs
new file mode 100644
index 0000000..720e4ff
--- /dev/null
+++ b/tests/deduplication_tests.rs
@@ -0,0 +1,27 @@
+use tempfile::tempdir;
+
+use bakare::repository::Repository;
+use bakare::test::{assertions::*, source::TestSource};
+
+use proptest::prelude::*;
+
+proptest! {
+    #[test]
+    fn store_duplicated_files_just_once(contents in any::<[u8;3]>()) {
+        let source = TestSource::new().unwrap();
+        let repository_path = &tempdir().unwrap().into_path();
+        Repository::init(repository_path).unwrap();
+        assert_eq!(data_weight(&repository_path).unwrap(), 0);
+
+        backup_file_with_byte_contents(&source, &repository_path, "1", &contents).unwrap();
+        let first_weight = data_weight(&repository_path).unwrap();
+        assert!(first_weight > 0);
+
+        backup_file_with_byte_contents(&source, &repository_path, "2", &contents).unwrap();
+        let second_weight = data_weight(&repository_path).unwrap();
+        assert_eq!(first_weight, second_weight);
+
+        assert_restored_file_contents(repository_path, &source.file_path("1"), &contents).unwrap();
+        assert_restored_file_contents(repository_path, &source.file_path("2"), &contents).unwrap();
+    }
+}
diff --git a/tests/system_tests.rs b/tests/system_tests.rs
index 71c5c2f..5131acb 100644
--- a/tests/system_tests.rs
+++ b/tests/system_tests.rs
@@ -5,8 +5,6 @@ use bakare::backup;
 use bakare::repository::Repository;
 use bakare::test::{assertions::*, source::TestSource};
 
-use proptest::prelude::*;
-
 #[test]
 fn restore_multiple_files() -> Result<()> {
     let source = TestSource::new().unwrap();
@@ -81,27 +79,6 @@ fn newer_version_should_be_greater_than_earlier_version() -> Result<()> {
     Ok(())
 }
 
-proptest! {
-    #[test]
-    fn store_duplicated_files_just_once(contents in any::<[u8;3]>()) {
-        let source = TestSource::new().unwrap();
-        let repository_path = &tempdir().unwrap().into_path();
-        Repository::init(repository_path).unwrap();
-        assert_eq!(data_weight(&repository_path).unwrap(), 0);
-
-        backup_file_with_byte_contents(&source, &repository_path, "1", &contents).unwrap();
-        let first_weight = data_weight(&repository_path).unwrap();
-        assert!(first_weight > 0);
-
-        backup_file_with_byte_contents(&source, &repository_path, "2", &contents).unwrap();
-        let second_weight = data_weight(&repository_path).unwrap();
-        assert_eq!(first_weight, second_weight);
-
-        assert_restored_file_contents(repository_path, &source.file_path("1"), &contents).unwrap();
-        assert_restored_file_contents(repository_path, &source.file_path("2"), &contents).unwrap();
-    }
-}
-
 #[test]
 fn restore_latest_version_by_default() -> Result<()> {
     let source = TestSource::new().unwrap();