diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index dd205e8..e4c9e2b 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -1,4 +1,4 @@
 #Database connection strings
-#spring.data.mongodb.host=localhost
-#spring.data.mongodb.port=27017
-#spring.data.mongodb.database=spring-boot-project-example
+spring.data.mongodb.host=localhost
+spring.data.mongodb.port=27017
+spring.data.mongodb.database=spring-boot-project-example
diff --git a/src/test/java/evrentan/examples/springbootprojectexample/ICustomerServiceTest.java b/src/test/java/evrentan/examples/springbootprojectexample/ICustomerServiceTest.java
new file mode 100644
index 0000000..9c7f822
--- /dev/null
+++ b/src/test/java/evrentan/examples/springbootprojectexample/ICustomerServiceTest.java
@@ -0,0 +1,133 @@
+package evrentan.examples.springbootprojectexample;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import evrentan.examples.springbootprojectexample.dto.Customer;
+import evrentan.examples.springbootprojectexample.dto.CustomerRef;
+import evrentan.examples.springbootprojectexample.entity.CustomerEntity;
+import evrentan.examples.springbootprojectexample.impl.CustomerServiceImpl;
+import evrentan.examples.springbootprojectexample.mapper.CustomerMapper;
+import evrentan.examples.springbootprojectexample.repository.CustomerRepository;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+class ICustomerServiceTest {
+    @Mock
+    private CustomerRepository customerRepository;
+
+    @Mock
+    private CustomerMapper customerMapper;
+
+    @InjectMocks
+    private CustomerServiceImpl customerService;
+
+    @BeforeEach
+    void beforeEach() {
+        MockitoAnnotations.openMocks(this);
+    }
+
+    @Test
+    void createCustomer() {
+        //given
+        Customer customer = new Customer();
+        customer.setId("1");
+        customer.setCustomerFullName("John");
+        customer.setCustomerType("ACTIVE");
+
+        CustomerEntity customerEntity = new CustomerEntity();
+        customerEntity.setId("1");
+        customerEntity.setCustomerType("ACTIVE");
+        customerEntity.setCustomerFullName("John");
+
+        //when
+        when(customerMapper.toEntity(customer)).thenReturn(customerEntity);
+        when(customerRepository.save(any())).thenReturn(customerEntity);
+        when(customerMapper.toDto(customerEntity)).thenReturn(customer);
+
+        Customer customer2 = customerService.createCustomer(customer);
+
+        //then
+        verify(customerRepository, times(1)).save(any());
+        assertEquals(customer, customer2);
+    }
+
+    @Test
+    void getAllCustomerRefs() {
+        //given
+        Customer customer = new Customer();
+        customer.setId("1");
+        customer.setCustomerFullName("John");
+        customer.setCustomerType("ACTIVE");
+
+        CustomerEntity customerEntity = new CustomerEntity();
+        customerEntity.setId("1");
+        customerEntity.setCustomerType("ACTIVE");
+        customerEntity.setCustomerFullName("John");
+
+        //when
+        when(customerMapper.toEntity(customer)).thenReturn(customerEntity);
+        when(customerRepository.save(any())).thenReturn(customerEntity);
+        when(customerMapper.toDto(customerEntity)).thenReturn(customer);
+
+        //given
+        CustomerRef customerRef = new CustomerRef();
+        customerRef.setId("1");
+
+        List<CustomerRef> customerRefList = new ArrayList<>();
+        customerRefList.add(customerRef);
+
+        List<CustomerEntity> entityList = new ArrayList<>();
+        entityList.add(customerEntity);
+
+        when(customerMapper.toDtoRefList(any())).thenReturn(customerRefList);
+        when(customerRepository.findAll()).thenReturn(entityList);
+
+        List<CustomerRef> customerRefs = customerService.getAllCustomerRefs();
+
+        verify(customerMapper, times(1)).toDtoRefList(any());
+        verify(customerRepository, times(1)).findAll();
+
+        assertEquals(customerRefs, customerRefList);
+    }
+
+    @Test
+    void getCustomerById() {
+        //given
+        Customer customer = new Customer();
+        customer.setId("1");
+        customer.setCustomerFullName("John");
+        customer.setCustomerType("ACTIVE");
+
+        CustomerEntity customerEntity = new CustomerEntity();
+        customerEntity.setId("1");
+        customerEntity.setCustomerType("ACTIVE");
+        customerEntity.setCustomerFullName("John");
+
+        //when
+        when(customerMapper.toEntity(customer)).thenReturn(customerEntity);
+        when(customerRepository.save(any())).thenReturn(customerEntity);
+        when(customerMapper.toDto(customerEntity)).thenReturn(customer);
+
+        Customer customer2 = customerService.createCustomer(customer);
+
+        when(customerMapper.toDto(any())).thenReturn(customer);
+        when(customerRepository.findById(anyString())).thenReturn(Optional.of(customerEntity));
+
+        Customer customerExample = customerService.getCustomerById("1");
+
+        verify(customerRepository, times(1)).findById(anyString());
+
+        assertEquals(customerExample, customer2);
+    }
+}