Remove duplicates from history completer

src/completion/history.rs

@@ -1,4 +1,4 @@
-use std::ops::Deref;
+use std::{collections::HashSet, ops::Deref};
 
 use crate::{
     history::SearchQuery, menu_functions::parse_selection_char, Completer, History, Span,
@@ -25,8 +25,10 @@ impl<'menu> Completer for HistoryCompleter<'menu> {
             ))
             .expect("todo: error handling");
 
+        let mut seen_command_lines = HashSet::new();
         values
             .into_iter()
+            .filter(|value| seen_command_lines.insert(value.command_line.clone()))
             .map(|value| self.create_suggestion(line, pos, value.command_line.deref()))
             .collect()
     }
@@ -66,3 +68,48 @@ impl<'menu> HistoryCompleter<'menu> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use rstest::rstest;
+
+    use super::*;
+    use crate::*;
+
+    fn new_history_item(command_line: &str) -> HistoryItem {
+        HistoryItem {
+            id: None,
+            start_timestamp: None,
+            command_line: command_line.to_string(),
+            session_id: None,
+            hostname: None,
+            cwd: None,
+            duration: None,
+            exit_status: None,
+            more_info: None,
+        }
+    }
+
+    #[rstest]
+    #[case(vec![], "any", vec![])]
+    #[case(vec!["old match","recent match","between","recent match"], "match", vec!["recent match","old match"])]
+    #[case(vec!["a","b","c","a","b","c"], "", vec!["c","b","a"])]
+    fn complete_doesnt_return_duplicates(
+        #[case] history_items: Vec<&str>,
+        #[case] line: &str,
+        #[case] expected: Vec<&str>,
+    ) -> Result<()> {
+        let mut history = FileBackedHistory::new(history_items.len())?;
+        for history_item in history_items {
+            history.save(new_history_item(history_item))?;
+        }
+        let mut sut = HistoryCompleter::new(&history);
+        let actual: Vec<String> = sut
+            .complete(line, line.len())
+            .into_iter()
+            .map(|suggestion| suggestion.value)
+            .collect();
+        assert_eq!(actual, expected);
+        Ok(())
+    }
+}