test TextArea::undo after insert_str and delete_str

src/textarea.rs

@@ -763,7 +763,14 @@ impl<'a> TextArea<'a> {
         }
 
         self.yank = deleted.join("\n"); // TODO
-        self.push_history(EditKind::DeleteChunk(deleted, first_start), self.cursor);
+
+        let edit = if deleted.len() == 1 {
+            EditKind::DeleteStr(deleted.remove(0), first_start)
+        } else {
+            EditKind::DeleteChunk(deleted, first_start)
+        };
+        self.push_history(edit, self.cursor);
+
         true
     }
 

tests/textarea.rs

@@ -387,6 +387,11 @@ fn test_insert_str_multiple_lines() {
         assert!(t.insert_str(input), "{:?}", test);
         assert_eq!(t.cursor(), after_pos, "{:?}", test);
         assert_eq!(t.lines(), expected, "{:?}", test);
+
+        assert!(t.undo(), "undo: {:?}", test);
+        assert_eq!(t.lines(), before, "content after undo: {:?}", test);
+        let before_pos = (row as _, col as _);
+        assert_eq!(t.cursor(), before_pos, "cursor after undo: {:?}", test);
     }
 }
 
@@ -701,5 +706,9 @@ fn test_delete_str_delete_multiple_lines() {
         assert_eq!(t.cursor(), (row, col), "cursor position: {:?}", test);
         assert_eq!(t.lines(), after, "text buffer content: {:?}", test);
         assert_eq!(t.yank_text(), deleted, "yanked text: {:?}", test);
+
+        assert!(t.undo(), "undo: {:?}", test);
+        assert_eq!(t.lines(), before, "content after undo: {:?}", test);
+        assert_eq!(t.cursor(), (row, col), "cursor after undo: {:?}", test);
     }
 }