diff --git a/stdlib/src/csv.rs b/stdlib/src/csv.rs
index aac9fcef..33b6e035 100644
--- a/stdlib/src/csv.rs
+++ b/stdlib/src/csv.rs
@@ -73,3 +73,112 @@ impl StdlibRegistry {
         );
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::cell::RefCell;
+    use std::rc::Rc;
+    use techscript_runtime::context::{RuntimeConfig, RuntimeContext};
+    use techscript_runtime::value::RuntimeValue;
+
+    #[test]
+    fn test_csv_register() {
+        let mut registry = StdlibRegistry::default();
+        registry.register_csv();
+
+        let module = registry
+            .modules
+            .get("std.csv")
+            .expect("Module std.csv should be registered");
+        assert_eq!(module.name, "std.csv");
+        assert!(module.exports.contains_key("parse"));
+        assert!(module.exports.contains_key("stringify"));
+    }
+
+    #[test]
+    fn test_csv_parse() {
+        let mut registry = StdlibRegistry::default();
+        registry.register_csv();
+
+        let module = registry.modules.get("std.csv").unwrap();
+        let parse_fn = module.exports.get("parse").unwrap();
+
+        let mut ctx = RuntimeContext::new(RuntimeConfig::default());
+        let args = vec![RuntimeValue::Str("a,b,c\n1,2,3".to_string())];
+
+        let result = parse_fn.call(&mut ctx, args).unwrap();
+
+        if let RuntimeValue::List { items, .. } = result {
+            let rows = items.borrow();
+            assert_eq!(rows.len(), 2);
+
+            // row 1
+            if let RuntimeValue::List {
+                items: r1_items, ..
+            } = &rows[0]
+            {
+                let r1 = r1_items.borrow();
+                assert_eq!(r1[0].try_into_string().unwrap(), "a");
+                assert_eq!(r1[1].try_into_string().unwrap(), "b");
+                assert_eq!(r1[2].try_into_string().unwrap(), "c");
+            } else {
+                panic!("Row 1 is not a list");
+            }
+
+            // row 2
+            if let RuntimeValue::List {
+                items: r2_items, ..
+            } = &rows[1]
+            {
+                let r2 = r2_items.borrow();
+                assert_eq!(r2[0].try_into_string().unwrap(), "1");
+                assert_eq!(r2[1].try_into_string().unwrap(), "2");
+                assert_eq!(r2[2].try_into_string().unwrap(), "3");
+            } else {
+                panic!("Row 2 is not a list");
+            }
+        } else {
+            panic!("Result is not a list");
+        }
+    }
+
+    #[test]
+    fn test_csv_stringify() {
+        let mut registry = StdlibRegistry::default();
+        registry.register_csv();
+
+        let module = registry.modules.get("std.csv").unwrap();
+        let stringify_fn = module.exports.get("stringify").unwrap();
+
+        let mut ctx = RuntimeContext::new(RuntimeConfig::default());
+
+        let r1 = vec![
+            RuntimeValue::Str("a".to_string()),
+            RuntimeValue::Str("b".to_string()),
+            RuntimeValue::Str("c".to_string()),
+        ];
+        let row1 = RuntimeValue::List {
+            items: Rc::new(RefCell::new(r1)),
+            is_const: false,
+        };
+        let r2 = vec![
+            RuntimeValue::Int(1),
+            RuntimeValue::Int(2),
+            RuntimeValue::Int(3),
+        ];
+        let row2 = RuntimeValue::List {
+            items: Rc::new(RefCell::new(r2)),
+            is_const: false,
+        };
+
+        let args = vec![RuntimeValue::List {
+            items: Rc::new(RefCell::new(vec![row1, row2])),
+            is_const: false,
+        }];
+
+        let result = stringify_fn.call(&mut ctx, args).unwrap();
+
+        assert_eq!(result.try_into_string().unwrap(), "a,b,c\n1,2,3");
+    }
+}