diff --git a/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionController.java b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionController.java
new file mode 100644
index 000000000000..e7bb1c612a5d
--- /dev/null
+++ b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionController.java
@@ -0,0 +1,21 @@
+package com.baeldung.micronaut.testing;
+
+import io.micronaut.http.MediaType;
+import io.micronaut.http.annotation.Controller;
+import io.micronaut.http.annotation.Get;
+import io.micronaut.http.annotation.QueryValue;
+
+@Controller
+public class AdditionController {
+
+    private final AdditionService additionService;
+
+    public AdditionController(AdditionService additionService) {
+        this.additionService = additionService;
+    }
+
+    @Get(uri = "/sum", produces = MediaType.TEXT_PLAIN)
+    public Integer sum(@QueryValue("firstNumber") int firstNumber, @QueryValue("secondNumber") int secondNumber) {
+        return additionService.sum(firstNumber, secondNumber);
+    }
+}
diff --git a/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionService.java b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionService.java
new file mode 100644
index 000000000000..5f4daf539d59
--- /dev/null
+++ b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionService.java
@@ -0,0 +1,7 @@
+package com.baeldung.micronaut.testing;
+
+public interface AdditionService {
+
+    Integer sum(int a, int b);
+
+}
diff --git a/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionServiceImpl.java b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionServiceImpl.java
new file mode 100644
index 000000000000..d38708a1ba04
--- /dev/null
+++ b/microservices-modules/micronaut/src/main/java/com/baeldung/micronaut/testing/AdditionServiceImpl.java
@@ -0,0 +1,13 @@
+package com.baeldung.micronaut.testing;
+
+import jakarta.inject.Singleton;
+
+@Singleton
+public class AdditionServiceImpl implements AdditionService {
+
+    @Override
+    public Integer sum(int a, int b) {
+        return a + b;
+    }
+
+}
diff --git a/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceMockingUnitTest.java b/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceMockingUnitTest.java
new file mode 100644
index 000000000000..d1762392e92a
--- /dev/null
+++ b/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceMockingUnitTest.java
@@ -0,0 +1,47 @@
+package com.baeldung.micronaut.testing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import jakarta.inject.Inject;
+
+import org.junit.jupiter.api.Test;
+
+import io.micronaut.http.HttpRequest;
+import io.micronaut.http.client.HttpClient;
+import io.micronaut.http.client.annotation.Client;
+import io.micronaut.test.annotation.MockBean;
+import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
+
+@MicronautTest
+class AdditionServiceMockingUnitTest {
+
+    @Inject
+    AdditionService additionService;
+
+    @MockBean(AdditionService.class)
+    AdditionService additionService() {
+        return mock(AdditionService.class);
+    }
+
+    @Inject
+    @Client("/")
+    HttpClient client;
+
+    @Test
+    void givenAdditionService_whenAddingTwoIntegers_thenReturnSum() {
+        when(additionService.sum(2, 2)).thenReturn(4);
+        assertEquals(4, additionService.sum(2, 2));
+    }
+
+    @Test
+    void givenSumUrl_whenPassingTwoIntegersAsQuery_thenReturnSum() {
+
+        when(additionService.sum(20, 25)).thenReturn(45);
+        final Integer result = client.toBlocking()
+            .retrieve(HttpRequest.GET("/sum?firstNumber=20&secondNumber=25"), Integer.class);
+
+        assertEquals(45, result);
+    }
+}
\ No newline at end of file
diff --git a/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceUnitTest.java b/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceUnitTest.java
new file mode 100644
index 000000000000..506289e58190
--- /dev/null
+++ b/microservices-modules/micronaut/src/test/java/com/baeldung/micronaut/testing/AdditionServiceUnitTest.java
@@ -0,0 +1,22 @@
+package com.baeldung.micronaut.testing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import jakarta.inject.Inject;
+
+import org.junit.jupiter.api.Test;
+
+import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
+
+@MicronautTest(startApplication = false)
+class AdditionServiceUnitTest {
+
+    @Inject
+    AdditionService additionService;
+
+    @Test
+    void givenAdditionService_whenAddingTwoIntegers_thenReturnSum() {
+        assertEquals(4, additionService.sum(2, 2));
+    }
+}
+