Fix getting content of history

1 files changed, 41 insertions, 10 deletions

diff --git a/src/history.rs b/src/history.rs
index a032eaa..ce5ae26 100644
--- a/src/history.rs
+++ b/src/history.rs
@@ -25,6 +25,14 @@ impl FileHistory {
         Ok(file_history.context("Corrupted file history.")?)
     }
 
+    pub fn write_to_file(&self, file: &mut File) -> anyhow::Result<()> {
+        let encoded: Vec<u8> = serde_json::to_vec(self)?;
+        file.rewind()?;
+        file.set_len(0)?;
+        file.write_all(encoded.as_ref())?;
+        Ok(())
+    }
+
     pub fn cursor(&self) -> usize {
         self.cursor
     }
@@ -41,7 +49,7 @@ impl FileHistory {
 
     pub fn get_content(&self) -> Vec<u8> {
         let mut buffer = Vec::new();
-        for file_change in self.changes.iter().take(self.cursor) {
+        for file_change in self.changes.iter().take(self.cursor + 1) {
             if let FileChange::Updated(ref updated) = file_change {
                 for change in updated.iter() {
                     change.apply(&mut buffer)
@@ -53,14 +61,6 @@ impl FileHistory {
         buffer
     }
 
-    pub fn write_to_file(&self, file: &mut File) -> anyhow::Result<()> {
-        let encoded: Vec<u8> = serde_json::to_vec(self)?;
-        file.rewind()?;
-        file.set_len(0)?;
-        file.write_all(encoded.as_ref())?;
-        Ok(())
-    }
-
     pub fn set_cursor(&mut self, new_cursor: usize) {
         if new_cursor < self.changes.len() {
             self.cursor = new_cursor;
@@ -68,7 +68,7 @@ impl FileHistory {
             panic!(
                 "Out-of-bounds cursor for file history: {}, can be at most {}",
                 new_cursor,
-                self.changes.len()
+                self.changes.len() - 1
             );
         }
     }
@@ -92,3 +92,34 @@ pub enum FileChange {
     Updated(Vec<ContentChange>),
     Deleted,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_content() {
+        let stages = &[
+            "",
+            "hiii!",
+            "yes hii? this is a test.",
+            "yes bye! this is not a test.",
+        ];
+
+        let mut history = FileHistory::default();
+        history.add_change(FileChange::Updated(Vec::new()));
+
+        for old_index in 0..stages.len() - 1 {
+            let old = stages[old_index].as_bytes();
+            let new = stages[old_index + 1].as_bytes();
+
+            let stage_difference = ContentChange::diff(old, new);
+            history.add_change(FileChange::Updated(stage_difference));
+        }
+
+        for index in 0..stages.len() {
+            history.set_cursor(index);
+            assert_eq!(stages[index].as_bytes(), history.get_content());
+        }
+    }
+}