Write tests

tests/for_loop.rs

@@ -26,3 +26,48 @@ fn modify_value() {
         result
     );
 }
+
+#[test]
+fn modify_iteration_values() {
+    let result = interpret(
+        "
+            list = [1 2 3]
+            for i in list { i += i }
+            list
+            ",
+    );
+
+    assert_eq!(
+        Ok(Value::List(List::with_items(vec![
+            Value::Integer(2),
+            Value::Integer(3),
+            Value::Integer(4),
+        ]))),
+        result
+    );
+}
+
+#[test]
+fn r#break() {
+    let result = interpret(
+        "
+            list = []
+            for i in [1 2 3] {
+                if i > 2 {
+                    break
+                } else {
+                    list += i
+                }
+            }
+            list
+            ",
+    );
+
+    assert_eq!(
+        Ok(Value::List(List::with_items(vec![
+            Value::Integer(1),
+            Value::Integer(2),
+        ]))),
+        result
+    );
+}