fix: uncomment testAddition method and ExpressionParser instantiation in ExpressionParserTest

Author: sharrlotte

src/test/java/ExpressionParserTest.java

@@ -4,16 +4,18 @@
 
 import org.junit.jupiter.api.Test;
 
+import mindustrytool.workflow.expressions.ExpressionParser;
+
 
 public class ExpressionParserTest {
-    // ExpressionParser parser = new ExpressionParser();
+    ExpressionParser parser = new ExpressionParser();
 
     Map<String, Object> variables = Map.of("a", 1, "b", 2);
 
-    // @Test
-    // void testAddition() {
-    //     assertEquals(parser.evaluateAsDouble("1 + 2", variables), 3);
-    // }
+    @Test
+    void testAddition() {
+        assertEquals(parser.evaluateAsDouble("1 + 2", variables), 3);
+    }
 
     @Test
     void test(){