Add unit test for value aliasing

lib/reader/src/parser.rs

@@ -1638,6 +1638,25 @@ mod tests {
         assert_eq!(message, "expected argument type");
     }
 
+    #[test]
+    fn aliases() {
+        let (func, details) = Parser::new("function qux() {
+                                           ebb0:
+                                             v4 = iconst.i8 6
+                                             vx3 -> v4
+                                             v1 = iadd_imm vx3, 17
+                                           }")
+                .parse_function(None)
+                .unwrap();
+        assert_eq!(func.name.to_string(), "qux");
+        let v4 = details.map.lookup_str("v4").unwrap();
+        assert_eq!(v4.to_string(), "v0");
+        let vx3 = details.map.lookup_str("vx3").unwrap();
+        assert_eq!(vx3.to_string(), "vx0");
+        let aliased_to = func.dfg.resolve_aliases(Value::table_with_number(0).unwrap());
+        assert_eq!(aliased_to.to_string(), "v0");
+    }
+
     #[test]
     fn signature() {
         let sig = Parser::new("()").parse_signature(None).unwrap();