diff --git a/liquidjava-verifier/pom.xml b/liquidjava-verifier/pom.xml
index af57236d..ba06b330 100644
--- a/liquidjava-verifier/pom.xml
+++ b/liquidjava-verifier/pom.xml
@@ -61,6 +61,45 @@
 	<build>
 		<finalName>${jar.finalName}</finalName>
 		<plugins>
+		<plugin>
+<groupId>org.jacoco</groupId>
+<artifactId>jacoco-maven-plugin</artifactId>
+<version>0.8.14</version>
+<executions>
+<execution>
+<id>default-prepare-agent</id>
+<goals>
+<goal>prepare-agent</goal>
+</goals>
+</execution>
+<execution>
+<id>default-report</id>
+<goals>
+<goal>report</goal>
+</goals>
+</execution>
+<execution>
+<id>default-check</id>
+<goals>
+<goal>check</goal>
+</goals>
+<configuration>
+<rules>
+<rule>
+<element>BUNDLE</element>
+<limits>
+<limit>
+<counter>COMPLEXITY</counter>
+<value>COVEREDRATIO</value>
+<minimum>0.60</minimum>
+</limit>
+</limits>
+</rule>
+</rules>
+</configuration>
+</execution>
+</executions>
+</plugin>
 			<plugin>
 				<groupId>net.revelc.code.formatter</groupId>
 				<artifactId>formatter-maven-plugin</artifactId>
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralString.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralString.java
new file mode 100644
index 00000000..5ed1ffcb
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralString.java
@@ -0,0 +1,25 @@
+package liquidjava.rj_language;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import org.junit.Test;
+
+import liquidjava.rj_language.ast.LiteralString;
+
+public class TestLiteralString {
+    @Test
+    public void testLiteralString() {
+        LiteralString s1 = new LiteralString("hello");
+        LiteralString s2 = new LiteralString("world");
+        assertNotEquals(s1.hashCode(), s2.hashCode());
+    }
+
+    @Test
+    public void testToString() {
+        LiteralString string = new LiteralString("hello world");
+
+        String result = string.toString();
+
+        assertEquals("hello world", result);
+    }
+}
\ No newline at end of file
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/opt/ExpressionSimplifierTest.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/ExpressionSimplifierTest.java
similarity index 100%
rename from liquidjava-verifier/src/test/java/liquidjava/rj_language/opt/ExpressionSimplifierTest.java
rename to liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/ExpressionSimplifierTest.java
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/TestOptimization.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/TestOptimization.java
new file mode 100644
index 00000000..2a596127
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/TestOptimization.java
@@ -0,0 +1,48 @@
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+import liquidjava.rj_language.ast.BinaryExpression;
+import liquidjava.rj_language.ast.LiteralInt;
+import liquidjava.rj_language.opt.ConstantFolding;
+import liquidjava.rj_language.opt.derivation_node.ValDerivationNode;
+
+public class TestOptimization {
+    @Test
+    public void testBinaryFold() {
+        BinaryExpression b = new BinaryExpression(new LiteralInt(1), "+", new LiteralInt(2));
+
+        ValDerivationNode r = ConstantFolding.fold(new ValDerivationNode(b, null));
+        assertEquals(r.getValue(), new LiteralInt(3));
+    }
+
+    @Test
+    public void testBinaryExpressionWithLiteralInt() {
+        LiteralInt num1 = new LiteralInt(40);
+        LiteralInt num2 = new LiteralInt(60);
+
+        BinaryExpression expression = new BinaryExpression(num1, "+", num2);
+
+        String result = expression.toString();
+
+        assertEquals("40 + 60", result);
+    }
+
+    @Test
+    public void testIntegrationNestedAddition() {
+        // Create integer literals
+        LiteralInt num1 = new LiteralInt(5);
+        LiteralInt num2 = new LiteralInt(10);
+        LiteralInt num3 = new LiteralInt(20);
+
+        // Create nested binary expressions
+        BinaryExpression firstSum = new BinaryExpression(num1, "+", num2); // 5 + 10
+        BinaryExpression nestedSum = new BinaryExpression(firstSum, "+", num3); // (5 + 10) + 20
+
+        // Convert to string
+        String result = nestedSum.toString();
+
+        // Expected output: "(5 + 10) + 20"
+        assertEquals("5 + 10 + 20", result);
+    }
+
+}
\ No newline at end of file
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/opt/VariableResolverTest.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/VariableResolverTest.java
similarity index 100%
rename from liquidjava-verifier/src/test/java/liquidjava/rj_language/opt/VariableResolverTest.java
rename to liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/opt/VariableResolverTest.java