diff --git a/src/prehandle.rs b/src/prehandle.rs
index 6eb93a6..1eace6d 100644
--- a/src/prehandle.rs
+++ b/src/prehandle.rs
@@ -23,9 +23,6 @@ fn filter_by_string(reader: Vec<String>, filter_str: &str) ->Vec<String>{
 }
 
 fn take(reader: &mut Vec<String>, start_index: u32, end_index: u32) -> Vec<String> {
-    if end_index < 0 && start_index < 0{
-        panic!("start_index and end_index must be positive");
-    }
     if end_index == 0 && start_index == 0{
         return reader.to_owned();
     }
@@ -40,4 +37,24 @@ fn take(reader: &mut Vec<String>, start_index: u32, end_index: u32) -> Vec<Strin
         body.append(&mut reader[start_index as usize..].to_owned());
     }
     body
+}
+
+#[cfg(test)]
+mod test{
+    #[test]
+    fn test_filter_by_string(){
+        let reader = vec!["a".to_string(), "b".to_string(), "c".to_string()];
+        let filter_str = "a";
+        let result = super::filter_by_string(reader, filter_str);
+        assert_eq!(result, vec!["a".to_string()]);
+    }
+
+    #[test]
+    fn test_take(){
+        let reader = vec!["a".to_string(), "b".to_string(), "c".to_string()];
+        let start_index = 1;
+        let end_index = 2;
+        let result = super::take(&mut reader.to_owned(), start_index, end_index);
+        assert_eq!(result, vec!["a".to_string(), "b".to_string()]);
+    }
 }
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