1 files changed, 53 insertions, 0 deletions

diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index eaeeeb97b..e32a0a0c3 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -11,11 +11,13 @@ pub mod mark;
 mod fixture;
 
 use std::{
+    convert::{TryFrom, TryInto},
     env, fs,
     path::{Path, PathBuf},
 };
 
 use serde_json::Value;
+use stdx::lines_with_ends;
 use text_size::{TextRange, TextSize};
 
 pub use difference::Changeset as __Changeset;
@@ -159,6 +161,57 @@ pub fn add_cursor(text: &str, offset: TextSize) -> String {
     res
 }
 
+/// Extracts `//^ some text` annotations
+pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
+    let mut res = Vec::new();
+    let mut prev_line_start: Option<TextSize> = None;
+    let mut line_start: TextSize = 0.into();
+    for line in lines_with_ends(text) {
+        if let Some(idx) = line.find("//^") {
+            let offset = prev_line_start.unwrap() + TextSize::of(&line[..idx + "//".len()]);
+            for (line_range, text) in extract_line_annotations(&line[idx + "//".len()..]) {
+                res.push((line_range + offset, text))
+            }
+        }
+        prev_line_start = Some(line_start);
+        line_start += TextSize::of(line);
+    }
+    res
+}
+
+fn extract_line_annotations(mut line: &str) -> Vec<(TextRange, String)> {
+    let mut res = Vec::new();
+    let mut offset: TextSize = 0.into();
+    while !line.is_empty() {
+        let len = line.chars().take_while(|&it| it == '^').count();
+        assert!(len > 0);
+        let range = TextRange::at(offset, len.try_into().unwrap());
+        let next = line[len..].find('^').map_or(line.len(), |it| it + len);
+        res.push((range, line[len..][..next - len].trim().to_string()));
+        line = &line[next..];
+        offset += TextSize::try_from(next).unwrap();
+    }
+    res
+}
+
+#[test]
+fn test_extract_annotations() {
+    let text = stdx::trim_indent(
+        r#"
+fn main() {
+    let (x,     y) = (9, 2);
+       //^ def  ^ def
+    zoo + 1
+} //^^^ i32
+    "#,
+    );
+    let res = extract_annotations(&text)
+        .into_iter()
+        .map(|(range, ann)| (&text[range], ann))
+        .collect::<Vec<_>>();
+    assert_eq!(res, vec![("x", "def".into()), ("y", "def".into()), ("zoo", "i32".into()),]);
+}
+
 // Comparison functionality borrowed from cargo:
 
 /// Compare a line with an expected pattern.