diff --git a/liquidjava-verifier/pom.xml b/liquidjava-verifier/pom.xml
index 5b42f4cb..673b0b5f 100644
--- a/liquidjava-verifier/pom.xml
+++ b/liquidjava-verifier/pom.xml
@@ -39,6 +39,45 @@
 				</configuration>
 			</plugin>
 			<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>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>${pVersion.compiler}</version>
diff --git a/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimization.java b/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimization.java
new file mode 100644
index 00000000..d99b0e7a
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimization.java
@@ -0,0 +1,18 @@
+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));
+    }
+}
\ No newline at end of file
diff --git a/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimizationInt.java b/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimizationInt.java
new file mode 100644
index 00000000..6e76382f
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimizationInt.java
@@ -0,0 +1,18 @@
+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 TestOptimizationInt {
+    @Test
+    public void testIntegerAddFold() {
+        BinaryExpression b = new BinaryExpression(new LiteralInt(2), "+", new LiteralInt(3));
+
+        ValDerivationNode r = ConstantFolding.fold(new ValDerivationNode(b, null));
+        assertEquals(new LiteralInt(5), r.getValue());
+    }
+}
\ No newline at end of file
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralInt.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralInt.java
new file mode 100644
index 00000000..a54a6595
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralInt.java
@@ -0,0 +1,24 @@
+package liquidjava.rj_language;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import liquidjava.rj_language.ast.LiteralInt;
+
+public class TestLiteralInt {
+
+    @Test
+    public void testLiteralIntEquality() {
+        LiteralInt a = new LiteralInt(10);
+        LiteralInt b = new LiteralInt(10);
+        assertEquals(a, b);
+    }
+
+    @Test
+    public void testLiteralIntHashCodeConsistency() {
+        LiteralInt a = new LiteralInt(5);
+        int firstHash = a.hashCode();
+        int secondHash = a.hashCode();
+        assertEquals(firstHash, secondHash);
+
+    }
+}
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..bb198e05
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralString.java
@@ -0,0 +1,14 @@
+package liquidjava.rj_language;
+
+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());
+    }
+}
\ No newline at end of file
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralStringExtra.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralStringExtra.java
new file mode 100644
index 00000000..f7615d42
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/TestLiteralStringExtra.java
@@ -0,0 +1,22 @@
+package liquidjava.rj_language;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import liquidjava.rj_language.ast.LiteralString;
+
+public class TestLiteralStringExtra {
+
+    @Test
+    public void testEqualStringsHaveEqualHashCodes() {
+        LiteralString s1 = new LiteralString("hello");
+        LiteralString s2 = new LiteralString("hello");
+        assertEquals(s1.hashCode(), s2.hashCode());
+    }
+
+    @Test
+    public void testDifferentStringsAreNotEqual() {
+        LiteralString s1 = new LiteralString("hello");
+        LiteralString s2 = new LiteralString("world");
+        assertNotEquals(s1, s2);
+    }
+}