Add assert_set_eq macro to make test clearer

Co-authored-by: Max Brunsfeld <max@zed.dev>

crates/util/src/test/marked_text.rs

@@ -0,0 +1,42 @@
+use std::{collections::HashMap, ops::Range};
+
+pub fn marked_text_by(
+    marked_text: &str,
+    markers: Vec<char>,
+) -> (String, HashMap<char, Vec<usize>>) {
+    let mut extracted_markers: HashMap<char, Vec<usize>> = Default::default();
+    let mut unmarked_text = String::new();
+
+    for char in marked_text.chars() {
+        if markers.contains(&char) {
+            let char_offsets = extracted_markers.entry(char).or_insert(Vec::new());
+            char_offsets.push(unmarked_text.len());
+        } else {
+            unmarked_text.push(char);
+        }
+    }
+
+    (unmarked_text, extracted_markers)
+}
+
+pub fn marked_text(marked_text: &str) -> (String, Vec<usize>) {
+    let (unmarked_text, mut markers) = marked_text_by(marked_text, vec!['|']);
+    (unmarked_text, markers.remove(&'|').unwrap_or_else(Vec::new))
+}
+
+pub fn marked_text_ranges(marked_text: &str) -> (String, Vec<Range<usize>>) {
+    let (unmarked_text, mut markers) = marked_text_by(marked_text, vec!['[', ']']);
+    let opens = markers.remove(&'[').unwrap_or_default();
+    let closes = markers.remove(&']').unwrap_or_default();
+    assert_eq!(opens.len(), closes.len(), "marked ranges are unbalanced");
+
+    let ranges = opens
+        .into_iter()
+        .zip(closes)
+        .map(|(open, close)| {
+            assert!(close >= open, "marked ranges must be disjoint");
+            open..close
+        })
+        .collect();
+    (unmarked_text, ranges)
+}