diff --git a/src/parser/filter_parser.rs b/src/parser/filter_parser.rs
index 3ff82d4..619d971 100644
--- a/src/parser/filter_parser.rs
+++ b/src/parser/filter_parser.rs
@@ -108,24 +108,35 @@ mod tests {
         let result = parse_filter_string("head_lines(10)").unwrap();
         assert_eq!(result.len(), 1);
         assert_eq!(result[0].name, "head_lines");
-        assert_eq!(result[0].options["head_lines"], 10);
+        assert_eq!(result[0].options.len(), 1);
+        if let serde_json::Value::Number(n) = result[0].options.get("head_lines").unwrap() {
+            assert_eq!(n.as_i64(), Some(10));
+        } else {
+            panic!("Expected number");
+        }
     }
     
     #[test]
     fn test_parse_filter_with_named_options() {
-        let result = parse_filter_string("grep(pattern=\"error\")").unwrap();
+        let result = parse_filter_string(r#"grep(pattern="error")"#).unwrap();
         assert_eq!(result.len(), 1);
         assert_eq!(result[0].name, "grep");
-        assert_eq!(result[0].options["pattern"], "error");
+        assert_eq!(result[0].options.get("pattern").unwrap().as_str(), Some("error"));
     }
     
     #[test]
     fn test_parse_multiple_filters() {
-        let result = parse_filter_string("head_lines(10)|grep(pattern=\"error\")").unwrap();
+        let result = parse_filter_string(r#"head_lines(10)|grep(pattern="error")"#).unwrap();
         assert_eq!(result.len(), 2);
         assert_eq!(result[0].name, "head_lines");
-        assert_eq!(result[0].options["head_lines"], 10);
+        assert_eq!(result[0].options.len(), 1);
+        if let serde_json::Value::Number(n) = result[0].options.get("head_lines").unwrap() {
+            assert_eq!(n.as_i64(), Some(10));
+        } else {
+            panic!("Expected number");
+        }
         assert_eq!(result[1].name, "grep");
-        assert_eq!(result[1].options["pattern"], "error");
+        assert_eq!(result[1].options.len(), 1);
+        assert_eq!(result[1].options.get("pattern").unwrap().as_str(), Some("error"));
     }
 }