Couple of small refinements to prefix / suffixes

Spotted when reviewing code; this uses native rust methods rather than specific slicing

cargo-insta/src/walk.rs

@@ -28,23 +28,25 @@ pub(crate) fn find_pending_snapshots<'a>(
     flags: FindFlags,
 ) -> impl Iterator<Item = Result<SnapshotContainer, Box<dyn Error>>> + 'a {
     make_snapshot_walker(package_root, extensions, flags)
-        .filter_map(|e| e.ok())
-        .filter_map(move |e| {
-            let fname = e.file_name().to_string_lossy();
-            if fname.ends_with(".new") {
-                let new_path = e.into_path();
-                let old_path = new_path.clone().with_extension("");
+        .filter_map(Result::ok)
+        .filter_map(|entry| {
+            let fname = entry.file_name().to_string_lossy();
+            let path = entry.clone().into_path();
+
+            #[allow(clippy::manual_map)]
+            if let Some(new_fname) = fname.strip_suffix(".new") {
                 Some(SnapshotContainer::load(
-                    new_path,
-                    old_path,
+                    path.clone(),
+                    path.with_file_name(new_fname),
                     SnapshotKind::File,
                 ))
-            } else if fname.starts_with('.') && fname.ends_with(".pending-snap") {
-                let mut target_path = e.path().to_path_buf();
-                target_path.set_file_name(&fname[1..fname.len() - 13]);
+            } else if let Some(new_fname) = fname
+                .strip_prefix('.')
+                .and_then(|f| f.strip_suffix(".pending-snap"))
+            {
                 Some(SnapshotContainer::load(
-                    e.path().to_path_buf(),
-                    target_path,
+                    path.clone(),
+                    path.with_file_name(new_fname),
                     SnapshotKind::Inline,
                 ))
             } else {

insta/src/runtime.rs

@@ -95,15 +95,14 @@ fn is_doctest(function_name: &str) -> bool {
 }
 
 fn detect_snapshot_name(function_name: &str, module_path: &str) -> Result<String, &'static str> {
-    let mut name = function_name;
-
     // clean test name first
-    name = name.rsplit("::").next().unwrap();
-    let mut test_prefixed = false;
-    if name.starts_with("test_") {
-        name = &name[5..];
-        test_prefixed = true;
-    }
+    let name = function_name.rsplit("::").next().unwrap();
+
+    let (name, test_prefixed) = if let Some(stripped) = name.strip_prefix("test_") {
+        (stripped, true)
+    } else {
+        (name, false)
+    };
 
     // next check if we need to add a suffix
     let name = add_suffix_to_snapshot_name(Cow::Borrowed(name));