[wip] unit tests for file module

- testing for `compute_hash` and `check_hash`

src/file/checked.rs

@@ -100,6 +100,11 @@ impl<'t> FileTrait<'t> for Checked {
     }
 
     fn check_hash(&self, on_progress: impl Fn(u64)) -> crate::Result<()> {
-        super::check_hash(&self.path, self.size, self.hash.as_ref(), on_progress)
+        super::check_hash(
+            &self.path,
+            self.size,
+            self.hash.as_ref().map(String::as_str),
+            on_progress,
+        )
     }
 }

src/file/mod.rs

@@ -46,7 +46,7 @@ fn compute_hash(path: &Path, size: u64, mut on_progress: impl FnMut(u64)) -> cra
 fn check_hash(
     path: &Path,
     size: u64,
-    hash: Option<&String>,
+    hash: Option<&str>,
     on_progress: impl FnMut(u64),
 ) -> crate::Result<()> {
     let Some(expected) = hash else {
@@ -126,11 +126,11 @@ mod tests {
     fn compute_hash_as_expected() {
         for (&(content, size), expected_hash) in CASES.iter().zip(HASHES) {
             // to capture progress updates from `compute_hash`
+            let file = create_file(content);
             let mut read_total = 0;
             let callback = |n| read_total += n;
 
-            let hash = compute_hash(create_file(content).path(), size, callback)
+            let hash = compute_hash(file.path(), size, callback).expect("hash should succeed");
-                .expect("hash should succeed");
 
             assert_eq!(hash, expected_hash);
             assert_eq!(read_total, size);
@@ -138,7 +138,7 @@ mod tests {
     }
 
     #[test]
-    fn compute_hash_size_mismatch() {
+    fn hash_size_mismatch() {
         let bad_sizes = [
             36, // common pangram
             12, // simple greeting
@@ -151,18 +151,55 @@ mod tests {
         ];
 
         for (&(content, good_size), bad_size) in CASES.iter().zip(bad_sizes) {
+            let file = create_file(content);
             let callback = drop;
 
-            let err = compute_hash(create_file(content).path(), bad_size, callback)
+            let err_callback = |err| {
-                .expect_err("should get a size-mismatch error");
+                // check error
-
-            // make sure it's the Mismatch variant, and that it contains the original input
                 match err {
                     crate::Error::Mismatch { expected, actual } => {
                         assert_eq!(expected, bad_size.to_string());
                         assert_eq!(actual, good_size.to_string());
                     }
-                _ => panic!("Expected Error::Mismatch for input size `{bad_size}` but got {err:?}"),
+                    _ => panic!(
+                        "Expected Error::Mismatch for input size `{bad_size}` but got {err:?}"
+                    ),
+                };
+            };
+
+            compute_hash(file.path(), bad_size, callback)
+                .map_err(err_callback)
+                .expect_err("compute_hash should report a mismatch");
+
+            check_hash(file.path(), bad_size, Some("foobar"), callback)
+                .map_err(err_callback)
+                .expect_err("check_hash should report a mismatch");
+        }
+    }
+
+    #[test]
+    fn hash_value_mismatch() {
+        let bad_hashes = [
+            "invalid9k+SHfSdG5igXsRY2Sh+nvBSNlQkLxzM7NnP4JAHPeqLkyx7NkCluPxTLVBP47Xe+cwRbE5FM3NapGA", // common pangram
+            "", // simple greeting
+            "eGoC90IBWQPGxv2FJVLScpEvR0DhWEdhiobiG/cfVBnSXhAxr+5YUxOJZESTTrBLkDpoWxRIt1XVb3Aa/pvizg", // empty slice
+            "Hash", // single-byte
+        ];
+
+        for ((&(content, size), good_hash), bad_hash) in CASES.iter().zip(HASHES).zip(bad_hashes) {
+            let file = create_file(content);
+            let callback = drop;
+
+            let err = check_hash(file.path(), size, Some(&bad_hash.to_string()), callback)
+                .expect_err("check_hash should report a mismatch");
+
+            // check error
+            match err {
+                crate::Error::Mismatch { expected, actual } => {
+                    assert_eq!(expected, bad_hash);
+                    assert_eq!(actual, good_hash);
+                }
+                _ => panic!("Expected Error::Mismatch but got {err:?}"),
             }
         }
     }

src/file/uploading.rs

@@ -107,6 +107,11 @@ impl<'t> FileTrait<'t> for Uploading {
     }
 
     fn check_hash(&self, on_progress: impl Fn(u64)) -> crate::Result<()> {
-        super::check_hash(&self.path, self.size, self.hash.as_ref(), on_progress)
+        super::check_hash(
+            &self.path,
+            self.size,
+            self.hash.as_ref().map(String::as_str),
+            on_progress,
+        )
     }
 }