ProcessTestCoverage does not create HTML files

Have tried the example of ProcessTestCoverage where @Rule with ProcessEngineRule should leave a HTML file in target/process_test_coverage folder. It was mentioned that camunda.cfg.xml should be there

Method we followed- we want to avoid XML based configuration and JUNIT uses @SpringBootTest so autowiring of ProcessEngine can be done and the below is the code sample.

@SpringBootTest(classes=Application.class)
@ActiveProfiles(“test”)
@RunWith(SpringRunner.class)
public class FlowTest_3 {

@Autowired
 ProcessEngine engine;  

@Rule
public ProcessEngineRule rule=new ProcessEngineRule(engine);

}

Even used camunda.cfg.xml file as shown below.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

  <bean id="processEngineConfiguration" class="org.camunda.bpm.extension.process_test_coverage.junit.rules.ProcessCoverageInMemProcessEngineConfiguration">

      <property name="databaseSchemaUpdate" value="true" />
  </bean>

</beans>    

When i use autowired processengine(With out enginerule and cfg.xml) it asserts but when i uncomment and uses the cfg.xml and engine rule it says assertion failed. I dont understand this behavior.

Considering beginners is there any self-enrollment course ? Can the XML config be avoided in spring-boot approach ? For now i removed cfg.xml but to generate HTML files in target folder i need to use ProcessEngineRule(which in-turn searches for cfg.xml). can anyone help me with this issue? Thanks in advance.