diff --git a/lib/ast/dune b/lib/ast/dune
new file mode 100644
index 0000000..ffbb18b
--- /dev/null
+++ b/lib/ast/dune
@@ -0,0 +1,3 @@
+(library
+ (name ast)
+ (modules syntax print))
diff --git a/lib/dune b/lib/dune
index 21805d8..100be86 100644
--- a/lib/dune
+++ b/lib/dune
@@ -10,10 +10,6 @@
  (modules parser)
  (libraries ast))
 
-(library
- (name ast)
- (modules ast))
-
 (menhir
  (modules parser))
 
diff --git a/test/ast.ml b/test/ast/print.ml
similarity index 85%
rename from test/ast.ml
rename to test/ast/print.ml
index 8ac9e05..80a4e64 100644
--- a/test/ast.ml
+++ b/test/ast/print.ml
@@ -1,7 +1,8 @@
-(* test/ast.ml *)
+(* test/print.ml *)
 
 open Alcotest
-open Ast
+open Ast.Syntax
+open Ast.Print
 
 let test_string_of_binary_operator () =
   check string "+" "Add" (string_of_binary_operator Add);
@@ -9,6 +10,9 @@ let test_string_of_binary_operator () =
   check string "*" "Multiply" (string_of_binary_operator Multiply);
   check string "/" "Divide" (string_of_binary_operator Divide)
 
+let test_string_of_unary_operator () =
+  check string "-" "Negate" (string_of_unary_operator Negate)
+
 let test_string_of_expression () =
   let expr = BinaryExpression (Add, IntegerLiteral 1, IntegerLiteral 2) in
   check string "1 + 2"
@@ -39,6 +43,11 @@ let () =
   let open Alcotest in
   run "AST tests"
     [
+      ( "string_of_unary_operator",
+        [
+          test_case "string_of_unary_operator" `Quick
+            test_string_of_unary_operator;
+        ] );
       ( "string_of_binary_operator",
         [
           test_case "string_of_binary_operator" `Quick
diff --git a/test/dune b/test/dune
index 6b4976a..d1a8ec0 100644
--- a/test/dune
+++ b/test/dune
@@ -1,5 +1 @@
-;test/dune
-
-(test
- (name ast)
- (libraries ast alcotest))
+;test/dune
\ No newline at end of file