[wip] unit tests for file module

- testing for `Checked`

src/file/checked.rs

@@ -115,20 +115,27 @@ impl FileTrait for Checked {
 
 #[cfg(test)]
 mod tests {
-    use tempfile::TempDir;
+    use tempfile::{NamedTempFile, TempDir};
 
     use crate::test_util::{
-        MockClient, create_file,
+        MockClient, check_trait, create_file,
         data::{HASHES_STD_GOOD, cases, data},
     };
 
     use super::*;
 
+    fn create_checked(content: &[u8]) -> (Checked, NamedTempFile) {
+        let file = create_file(content);
+        let chk = Checked::new(file.path()).expect("creating `Checked` should succeed");
+
+        // return both, so the `NamedTempFile` is not auto-deleted here
+        (chk, file)
+    }
+
     #[test]
     fn new_on_existing_file_works() {
         for (content, size) in cases() {
-            let file = create_file(content);
-            let chk = Checked::new(file.path()).expect("creating `Checked` should succeed");
+            let (chk, file) = create_checked(content);
 
             let path = file
                 .path()
@@ -145,6 +152,19 @@ mod tests {
                 file.path().file_name().expect("`file_name` should succeed")
             );
             assert_eq!(chk.get_size(), size);
+
+            check_trait(
+                chk.as_ref(),
+                path.as_os_str().as_encoded_bytes(),
+                "AsRef<u8>",
+                "Checked",
+            );
+
+            // new_direct
+            let chk = Checked::new_direct(chk.path, chk.size, chk.hash);
+            assert_eq!(chk.path, path);
+            assert_eq!(chk.size, size);
+            assert!(chk.hash.is_none());
         }
     }
 
@@ -179,8 +199,7 @@ mod tests {
     #[test]
     fn hashing_works() {
         for (content, hash) in data().zip(HASHES_STD_GOOD) {
-            let file = create_file(content);
-            let mut chk = Checked::new(file.path()).expect("creating `Checked` should succeed");
+            let (mut chk, _file) = create_checked(content);
 
             chk.hash(drop).expect("`hash` should succeed");
             // `FileTrait`
@@ -193,10 +212,10 @@ mod tests {
     #[test]
     fn hashing_again_errors() {
         for content in data() {
-            let file = create_file(content);
-            let mut chk = Checked::new(file.path()).expect("creating `Checked` should succeed");
+            let (mut chk, _file) = create_checked(content);
 
-            chk.hash(drop).expect("`hash` should succeed");
+            // fake hash
+            chk.hash = Some(String::default());
             let err = chk.hash(drop).expect_err("`hash` twice should fail");
 
             assert!(err.is_mismatch("unhashed file", chk.path.display().to_string()));
@@ -209,8 +228,7 @@ mod tests {
         let share_id = client.add_share();
 
         for content in data() {
-            let file = create_file(content);
-            let chk = Checked::new(file.path()).expect("creating `Checked` should succeed");
+            let (chk, _file) = create_checked(content);
 
             assert!(
                 chk.start_upload(