diff --git a/src/compiler/ast.rs b/src/compiler/ast.rs
index 4919a28..890ec87 100644
--- a/src/compiler/ast.rs
+++ b/src/compiler/ast.rs
@@ -3,6 +3,7 @@ pub enum Expression<'source> {
     IntLiteral(u32),
     BoolLiteral(bool),
     Identifier(&'source str),
+    UnaryOp(&'source str, Box<Expression<'source>>),
     BinaryOp(
         Box<Expression<'source>>,
         &'source str,
diff --git a/src/compiler/parser/tests.rs b/src/compiler/parser/tests.rs
index e675a5f..42d24c9 100644
--- a/src/compiler/parser/tests.rs
+++ b/src/compiler/parser/tests.rs
@@ -13,6 +13,12 @@ macro_rules! id_ast {
     };
 }
 
+macro_rules! un_ast {
+    ($x:expr, $y:expr) => {
+        Box::new(UnaryOp($x, $y))
+    };
+}
+
 macro_rules! bin_ast {
     ($x:expr, $y:expr, $z:expr) => {
         Box::new(BinaryOp($x, $y, $z))
@@ -122,6 +128,31 @@ fn test_binary_op_precedence() {
     );
 }
 
+#[test]
+fn test_assignment() {
+    let result = parse(&tokenize("a = b = 1 + 2"));
+    assert_eq!(
+        result,
+        BinaryOp(
+            id_ast!("a"),
+            "=",
+            bin_ast!(id_ast!("b"), "=", bin_ast!(int_ast!(1), "+", int_ast!(2)))
+        )
+    );
+}
+
+#[test]
+fn test_unary() {
+    let result = parse(&tokenize("not not x"));
+    assert_eq!(result, UnaryOp("not", un_ast!("not", id_ast!("x"))));
+
+    let result = parse(&tokenize("--x"));
+    assert_eq!(result, UnaryOp("-", un_ast!("-", id_ast!("x"))));
+
+    let result = parse(&tokenize("--1"));
+    assert_eq!(result, UnaryOp("-", un_ast!("-", int_ast!(1))));
+}
+
 #[test]
 fn test_parenthesized() {
     let result = parse(&tokenize("(1+2)*3"));