More expression parsing
diff --git a/tests/test_expr.rs b/tests/test_expr.rs
new file mode 100644
index 0000000..75bee8a
--- /dev/null
+++ b/tests/test_expr.rs
@@ -0,0 +1,15 @@
+#![cfg(feature = "full")]
+
+extern crate syn;
+use syn::*;
+
+#[test]
+fn test_box() {
+    let raw = "box 0";
+
+    let expected = Expr::Box(Box::new(
+        Expr::Lit(Lit::Int(0, IntTy::Unsuffixed))
+    ));
+
+    assert_eq!(expected, parse_expr(raw).unwrap());
+}