diff --git a/liquidjava-verifier/pom.xml b/liquidjava-verifier/pom.xml
index 5b42f4cb..19a19d11 100644
--- a/liquidjava-verifier/pom.xml
+++ b/liquidjava-verifier/pom.xml
@@ -10,7 +10,7 @@
 	</parent>
 
 	<groupId>liquidjava-verifier
-		</groupId>
+	</groupId>
 	<artifactId>liquidjava-verifier</artifactId>
 	<version>5.2-SNAPSHOT</version>
 	<name>liquidjava-verifier</name>
@@ -77,7 +77,8 @@
 						</goals>
 						<configuration>
 							<transformers>
-								<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+								<transformer
+									implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
 									<mainClass>liquidjava.api.CommandLineLauncher</mainClass>
 								</transformer>
 							</transformers>
@@ -95,6 +96,45 @@
 					</execution>
 				</executions>
 			</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>0.50</minimum>
+										</limit>
+									</limits>
+								</rule>
+							</rules>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 
@@ -206,4 +246,4 @@
 			</dependency>
 		</dependencies>
 	</dependencyManagement>
-</project>
+</project>
\ No newline at end of file
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..e7849ad9
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/ast/opt/TestOptimization.java
@@ -0,0 +1,17 @@
+package liquidjava.rj_language.ast.opt;
+
+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));
+    }
+}
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..7e82772f
--- /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());
+    }
+}
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBinaryTypeIntegration.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBinaryTypeIntegration.java
new file mode 100644
index 00000000..47342c83
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBinaryTypeIntegration.java
@@ -0,0 +1,37 @@
+package liquidjava.rj_language.ast.typing;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import liquidjava.rj_language.ast.*;
+import liquidjava.processor.context.Context;
+import spoon.Launcher;
+import spoon.reflect.factory.Factory;
+import java.util.Optional;
+import spoon.reflect.reference.CtTypeReference;
+
+public class TestBinaryTypeIntegration {
+
+    @Test
+    public void testBinaryIntExpressionType() {
+        Launcher launcher = new Launcher();
+        Factory factory = launcher.getFactory();
+        Context ctx = null;
+
+        BinaryExpression expr = new BinaryExpression(new LiteralInt(1), "+", new LiteralInt(2));
+        Optional<CtTypeReference<?>> result = TypeInfer.getType(ctx, factory, expr);
+        assertTrue(result.isPresent());
+        assertEquals("int", result.get().getSimpleName().toLowerCase());
+    }
+
+    @Test
+    public void testBinaryBooleanExpressionType() {
+        Launcher launcher = new Launcher();
+        Factory factory = launcher.getFactory();
+        Context ctx = null;
+
+        BinaryExpression expr = new BinaryExpression(new LiteralBoolean(true), "&&", new LiteralBoolean(false));
+        Optional<CtTypeReference<?>> result = TypeInfer.getType(ctx, factory, expr);
+        assertTrue(result.isPresent());
+        assertEquals("boolean", result.get().getSimpleName().toLowerCase());
+    }
+}
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBoolType.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBoolType.java
new file mode 100644
index 00000000..0f347fa6
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestBoolType.java
@@ -0,0 +1,26 @@
+package liquidjava.rj_language.ast.typing;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import spoon.Launcher;
+import spoon.reflect.factory.Factory;
+import liquidjava.processor.context.Context;
+import liquidjava.rj_language.ast.*;
+import java.util.Optional;
+import spoon.reflect.reference.CtTypeReference;
+
+public class TestBoolType {
+
+    @Test
+    public void testBooleanLiteralType() {
+        Launcher launcher = new Launcher();
+        Factory factory = launcher.getFactory();
+        Context ctx = null;
+
+        LiteralBoolean boolExpr = new LiteralBoolean(true);
+        Optional<CtTypeReference<?>> result = TypeInfer.getType(ctx, factory, boolExpr);
+
+        assertTrue(result.isPresent());
+        assertEquals("boolean", result.get().getSimpleName().toLowerCase());
+    }
+}
diff --git a/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestCheckCompatibleType.java b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestCheckCompatibleType.java
new file mode 100644
index 00000000..d32db786
--- /dev/null
+++ b/liquidjava-verifier/src/test/java/liquidjava/rj_language/ast/typing/TestCheckCompatibleType.java
@@ -0,0 +1,35 @@
+package liquidjava.rj_language.ast.typing;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import liquidjava.rj_language.ast.*;
+import liquidjava.processor.context.Context;
+import spoon.Launcher;
+import spoon.reflect.factory.Factory;
+
+public class TestCheckCompatibleType {
+
+    @Test
+    public void testCompatibleLiterals() {
+        Launcher launcher = new Launcher();
+        Factory factory = launcher.getFactory();
+        Context ctx = null;
+
+        LiteralInt a = new LiteralInt(3);
+        LiteralInt b = new LiteralInt(4);
+
+        assertTrue(TypeInfer.checkCompatibleType(a, b, ctx, factory));
+    }
+
+    @Test
+    public void testIncompatibleLiterals() {
+        Launcher launcher = new Launcher();
+        Factory factory = launcher.getFactory();
+        Context ctx = null;
+
+        LiteralInt a = new LiteralInt(3);
+        LiteralString s = new LiteralString("abc");
+
+        assertFalse(TypeInfer.checkCompatibleType(a, s, ctx, factory));
+    }
+}