How to Mock HikariDataSource and DataSourceProperties? - spring-boot

Question

How can I mock HikariDataSource and DataSourceProperties using springboot and Junit5 and Mockito?
I found one possible solution but it seems to be rather very lengthy approach to test a single method, you can check here
I am trying to unit test one of the method 'ping' in my class but getting exception:
java.lang.NullPointerException
at com.my.app.configuration.DbConfigurationTest.shouldReturnPing(DbConfgiurationTest.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:532)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:171)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
Test Class:
import com.my.app.config.DbConfiguration;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mockito;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.test.context.TestConfiguration;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.is;
import static org.mockito.Mockito.when;
#TestConfiguration
class DbConfigurationTest
{
#InjectMocks static DbConfiguration dbConfiguration;
DataSourceProperties dataSourceProperties= Mockito.mock(DataSourceProperties.class);
#Test
public void shouldReturnPing()
{
// expect
boolean expectedResult = true;
when(dbConfiguration.dataSourceProperties()).thenReturn(dataSourceProperties);
when(dbConfiguration.dataSource(dataSourceProperties).isRunning()).thenReturn(true);
boolean actualResult = dbConfiguration.ping();
assertThat(actualResult, is(equalTo(expectedResult)));
}
}
Method class which needs to be tested:
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
/**
* Database configuration. Only properties override is required, everything else comes from spring boot auto-config.
*/
#Configuration
public class DbConfiguration
{
/**
* Overrides the auto-configured bean in order to specify a different prefix for the DataSourceProperties
*
* #return A DataSourceProperties bean
*/
#Bean
#Primary
#ConfigurationProperties("my.datasource")
public DataSourceProperties dataSourceProperties()
{
return new DataSourceProperties();
}
/**
* Overrides the {#link javax.sql.DataSource} bean creation from
* {#link org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration}
* to specify a different prefix for the {#link org.springframework.boot.context.properties.ConfigurationProperties}
*
* #param dataSourceProperties The properties to configure the datasource
* #return A {#link com.zaxxer.hikari.HikariDataSource} instance
*/
#Bean
#ConfigurationProperties("my.datasource.configuration")
public HikariDataSource dataSource(final DataSourceProperties dataSourceProperties)
{
return dataSourceProperties.initializeDataSourceBuilder().type(HikariDataSource.class).build();
}
/**
* Ping the service.
*
* #return the boolean
*/
public boolean ping()
{
return dataSource(dataSourceProperties()).isRunning();
}
}
How can I successfully test the 'ping' method? I tried to create mock but failed.
Thanks in advance :)

Answer 1

I would suggest moving the ping() method to a separate class and autowire the DataSource there. For example:
#Component
public class DatabaseHealthCheck {
public DatabaseHealthCheck(HikariDataSource dataSource) {
this.dataSource = dataSource;
}
public boolean ping() {
return dataSource.isRunning();
}
}
And now you can test it like this:
// Mock only the DataSource, either with #Mock or like this
HikariDataSource dataSource = mock(HikariDataSource.class);
DatabaseHealthCheck healthCheck = new DatabaseHealthCheck(dataSource);
when(dataSource.isRunning()).thenReturn(true);
assertThat(healthCheck.ping()).isTrue();