Unit Test - Microservices - Business Layer

In this post, I am going to show how to unit test the business layer of the lead microservice that I am developing. A couple of things to keep in mind to write the unit test for the business layer.

1. These tests run must very fast for quick feedback.
2. Only the business layer is involved and hence the web layer and repository layer should not be started. In other words, the Spring web tier beans should not be created and neither any database connections should be used. (This helps to achieve #1). 
3. The repository layer will be mocked using Mockito.
4. The fluent assert from AssertJ library will be used. 

The source code of the lead business unit test is shown in listing below.

	package com.effectiv.crm.business.ut;
	import static org.mockito.Matchers.any;
	import static org.mockito.Mockito.times;
	import static org.mockito.Mockito.verify;
	import static org.mockito.Mockito.verifyNoMoreInteractions;
	import static org.mockito.Mockito.when;
	import static org.assertj.core.api.Assertions.*;
	import java.util.ArrayList;
	import java.util.List;
	import org.junit.Before;
	import org.junit.Test;
	import org.mockito.ArgumentCaptor;
	import org.mockito.Mockito;
	import org.springframework.data.domain.Page;
	import org.springframework.data.domain.PageImpl;
	import org.springframework.data.domain.PageRequest;
	import org.springframework.data.domain.Pageable;
	import com.effectiv.crm.business.LeadBusinessDelegate;
	import com.effectiv.crm.domain.Lead;
	import com.effectiv.crm.repository.LeadRepository;
	public class LeadBusinessDelegateTest {
	private LeadBusinessDelegate leadBusinessDelegate;
	private LeadRepository leadRepository;
	@Before
	public void setUp() {
	leadRepository = Mockito.mock(LeadRepository.class);
	leadBusinessDelegate = new LeadBusinessDelegate(leadRepository);
	}
	@Test
	public void findOne() {
	Lead l = new Lead();
	l.setId("1");
	l.setFirstName("Virat");
	l.setLastName("Kohli");
	// mock
	when(leadRepository.findOne(any(String.class))).thenReturn(l);
	Lead rl = leadBusinessDelegate.findOne("1");
	assertThat(rl.getId()).isEqualTo("1");
	assertThat(rl.getFirstName()).isEqualTo("Virat");
	assertThat(rl.getLastName()).isEqualTo("Kohli");
	verify(leadRepository, times(1)).findOne("1");
	verifyNoMoreInteractions(leadRepository);
	}
	@Test
	public void findOneDoesNotExist() {
	// mock
	when(leadRepository.findOne(any(String.class))).thenReturn(null);
	Lead rl = leadBusinessDelegate.findOne("1");
	assertThat(rl).isNull();
	verify(leadRepository, times(1)).findOne("1");
	verifyNoMoreInteractions(leadRepository);
	}
	@Test
	public void testFindAll() {
	List<Lead> leads = new ArrayList<Lead>();
	Lead l = new Lead();
	l.setId("1");
	leads.add(l);
	l = new Lead();
	l.setId("2");
	leads.add(l);
	l = new Lead();
	l.setId("3");
	leads.add(l);
	l = new Lead();
	l.setId("4");
	leads.add(l);
	l = new Lead();
	l.setId("5");
	leads.add(l);
	when(leadRepository.findAll(any(Pageable.class))).thenReturn(new PageImpl<>(leads));
	PageRequest p = new PageRequest(1, 5);
	Page<Lead> rLeadPage = leadBusinessDelegate.findAll(p);
	assertThat(rLeadPage.getTotalElements()).isEqualTo(5L);
	assertThat(rLeadPage.getTotalPages()).isEqualTo(1);
	List<Lead> rLeads = rLeadPage.getContent();
	int counter = 1;
	for (Lead ld : rLeads) {
	assertThat(ld.getId()).isEqualTo(counter + "");
	counter++;
	}
	verify(leadRepository, times(1)).findAll(p);
	verifyNoMoreInteractions(leadRepository);
	}
	@Test
	public void testSave() {
	Lead lead = new Lead();
	lead.setAnnualRevenue(50000.00D);
	lead.setCompany("EFFECTIV");
	lead.setDeleted(false);
	lead.setDescription("Unit - test - entity :: Lead");
	lead.setDesignation("Project Manager");
	lead.setEmail("effectvlead@effectiv.com");
	lead.setEmailOptOut(false);
	lead.setId("1");
	// mock
	when(leadRepository.save(any(Lead.class))).thenReturn(lead);
	Lead rLead = leadBusinessDelegate.save(lead);
	assertThat(rLead).isNotNull();
	assertThat(rLead.getId()).isEqualTo("1"); //ensure that ID does not change and lead object is returned
	verify(leadRepository, times(1)).save(lead);
	verifyNoMoreInteractions(leadRepository);
	}
	@Test
	public void testDelete() {
	// mock
	Lead lead = new Lead();
	lead.setAnnualRevenue(50000.00D);
	lead.setCompany("EFFECTIV");
	lead.setDeleted(false);
	lead.setDescription("Unit - test - entity :: Lead");
	lead.setDesignation("Project Manager");
	lead.setEmail("effectvlead@effectiv.com");
	lead.setEmailOptOut(false);
	lead.setId("1");
	// mock
	when(leadRepository.findOne(any(String.class))).thenReturn(lead);
	leadBusinessDelegate.delete("1");
	ArgumentCaptor<Lead> leadCaptor = ArgumentCaptor.forClass(Lead.class);
	verify(leadRepository, times(1)).findOne("1");
	verify(leadRepository, times(1)).save(leadCaptor.capture());
	verifyNoMoreInteractions(leadRepository);
	Lead deletedLead = leadCaptor.getValue();
	//check same lead
	assertThat(deletedLead.getId()).isEqualTo("1");
	//check if deleted flag is true
	assertThat(deletedLead.isDeleted()).isEqualTo(true);
	}
	}

view raw LeadBusinessDelegateTest.java hosted with ❤ by GitHub

Most of the test methods are straight forward. However, the testDelete the method needs some explanation. Here the findOne method is mocked/stubbed. This ensures that correct lead object is returned by the stub method. The other thing to note is that the verify the method for saving method captures the internal Lead object. Finally, that object is checked to verify that the "id" and "deleted" attributes. This ensures that the correct object was marked for soft delete by changing the "deleted" attribute.

I will pause the microservices test series for couple weeks. In the next post, I will write again about "12-factor app" and then introduce Spring Cloud Config Server and see how we can implement one key factor of cloud-native application. So, stay tuned.

The source code is available at - https://github.com/kdhrubo/playground/tree/develop/lead-backend