Revert oversimplifications

tests/example_document.rs

@@ -40,10 +40,9 @@ impl ExampleDocument {
     /// If the result string does not match the expected string, the program
     /// will panic.
     pub fn assert_eq(&self, result: &EditedText<'_, String>) {
-        let result_str = ExampleDocument::text_with_cursors_to_string(result);
         assert_eq!(
-            self.expected, result_str,
-            "Left (expected) isn't equal to right (actual). Actual: ```\n{result_str}```",
+            Self::string_to_text_with_cursors(&self.expected),
+            result.apply()
         );
     }
 
@@ -62,30 +61,6 @@ impl ExampleDocument {
         );
     }
 
-    fn text_with_cursors_to_string(document: &EditedText<'_, String>) -> String {
-        let merged = document.apply();
-        let mut result = merged.text();
-        for (i, cursor) in merged.cursors().iter().enumerate() {
-            assert!(
-                cursor.char_index() <= result.len(), // equals in case of insert at the end
-                "Cursor index out of bounds: {} > {} when testing for '{}.'",
-                cursor.char_index(),
-                result.len(),
-                result
-            );
-
-            result.insert(
-                result
-                    .char_indices()
-                    .nth(cursor.char_index() + i)
-                    .map_or_else(|| result.len(), |(byte_index, _)| byte_index), /* find the utf8 char index of the insert
-                                                                                  * in byte index */
-                '|',
-            );
-        }
-        result
-    }
-
     fn string_to_text_with_cursors(text: &str) -> TextWithCursors {
         let cursors = Self::parse_cursors(text);
         let text = text.replace('|', "");

tests/wasm.rs

@@ -1,6 +1,6 @@
 #![cfg(feature = "wasm")]
 
-use reconcile_text::{BuiltinTokenizer, CursorPosition, TextWithCursors, wasm::*};
+use reconcile_text::{BuiltinTokenizer, CursorPosition, EditedText, TextWithCursors, wasm::*};
 use wasm_bindgen_test::*;
 
 #[wasm_bindgen_test(unsupported = test)]
@@ -55,6 +55,16 @@ fn test_merge_binary() {
     );
 }
 
+#[wasm_bindgen_test(unsupported = test)]
+fn test_from_diff_rejects_oversized_lengths() {
+    for length in [1_i64 << 32, -(1_i64 << 40), i64::MAX, i64::MIN] {
+        let error = EditedText::from_diff("abc", vec![length.into()], &*BuiltinTokenizer::Word)
+            .unwrap_err();
+
+        assert!(error.to_string().starts_with("Invalid diff:"));
+    }
+}
+
 #[wasm_bindgen_test] // JsValue isn't supported outside of wasm
 fn test_diff() {
     let parent = "hello ";