diff --git a/tests/interpret.rs b/tests/interpret.rs
index ae1c846..ae27ea0 100644
--- a/tests/interpret.rs
+++ b/tests/interpret.rs
@@ -47,6 +47,50 @@ mod assignment {
     }
 }
 
+mod for_loop {
+    use dust_lang::*;
+
+    #[test]
+    fn simple_for_loop() {
+        let result = interpret("for i in [1 2 3] { output(i) }");
+
+        assert_eq!(Ok(Value::none()), result);
+    }
+
+    #[test]
+    fn modify_value() {
+        let result = interpret(
+            "
+            list = []
+            for i in [1 2 3] { list += i }
+            list
+            ",
+        );
+
+        assert_eq!(
+            Ok(Value::List(List::with_items(vec![
+                Value::Integer(1),
+                Value::Integer(2),
+                Value::Integer(3),
+            ]))),
+            result
+        );
+    }
+
+    #[test]
+    fn modify_value_async() {
+        let result = interpret(
+            "
+            list = []
+            async for i in [1 2 3] { list += i }
+            length(list)
+            ",
+        );
+
+        assert_eq!(Ok(Value::Integer(3)), result);
+    }
+}
+
 mod logic {
     use dust_lang::*;