Using actual properties file from src/main/resources with Spring @PropertySource in JUnit test

I am trying to unit test a DAO class by using a H2 database instead of an actual database. I am facing an issue while trying to make my test case use a properties file that is present in the src/main/resources/properties/ folder :

Test class

@RunWith(SpringJUnit4ClassRunner.class)
@PropertySource("classpath:properties/common.properties")
@ContextConfiguration(locations = { "/spring/common-context.xml" })
public class ConfigDAOImplTest {
	
	@Autowired
	private ConfigDAOImpl configDAO;

	@Spy
	private ContextParamDAO contextParamDAO = new ContextParamDAOImpl();

	private static final String SCHEMA_CONFIG = "classpath:data/CONFIG_SCHEMA.sql";
	private static final String DATA_CONFIG = "classpath:data/CONFIG_DATA.sql";

	@Before
	public void init() {
		MockitoAnnotations.initMocks(this);

		DataSource dataSource = new EmbeddedDatabaseBuilder()
				.setType(EmbeddedDatabaseType.H2)
				.addScript(SCHEMA_CONFIG)
				.addScript(DATA_CONFIG)
				.build();
		
		JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

        //override the jdbcTemplate for the test case    
		configDAO.setJdbcTemplate(jdbcTemplate);
		configDAO.setContextParamDAO(contextParamDAO);
		

	}

    //.. more coode
}

common-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:batch="http://www.springframework.org/schema/batch"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans-2.5.xsd		
		http://www.springframework.org/schema/tx 
		http://www.springframework.org/schema/tx/spring-tx-2.5.xsd     	
     	http://www.springframework.org/schema/batch 
     	http://www.springframework.org/schema/batch/spring-batch.xsd
     	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="commonAppProperties"
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="ignoreResourceNotFound" value="true" />
		<property name="ignoreUnresolvablePlaceholders" value="true" />
		<property name="locations">
			<list>
				<value>file:${conf_folder_path}/common.properties</value>
			</list>
		</property>
	</bean>

    <bean id="configDAO"
		class="com.myproject.common.dataaccess.impl.ConfigDAOImpl" scope="step">
		<property name="jdbcTemplate" ref="jdbcTemplate" />
        <property name="corePoolSize" value="${threadpool.size}"/>
    </bean>
</beans>

When I run the test class, I get the following exception :

Caused by: org.springframework.beans.TypeMismatchException: Failed to convert property value of type 'java.lang.String' to required type 'int' for property 'corePoolSize'; nested exception is java.lang.NumberFormatException: For input string: "${threadpool.size}"

One reason for the test case not being able to find the required property is because :

1. The PropertyPlaceholderConfigurer bean refers to
   {conf_folder_path}/common.properties which is the path where
   src/main/resources/properties/common.properties gets copied to by Maven build system.
2. However , in Eclipse, there is no {conf_folder_path} as this is created by Maven.

Question : Assumnig that the above reason is the root cause of the issue, how do I make the test case find the properties considering the path refereed to in the Spring context is different from that in the source code.

You can create something like this:

@Configuration
public class TestConfiguration {

    private static final Logger log = LoggerFactory.getLogger(TestConfiguration.class);

    @Autowired
    private Environment env;

    /**
     * This bean is necessary in order to use property file from src/main/resources/properties
     * @param env environment
     * @return property source configurator with correct property file
     */
    @Bean
    public PropertySourcesPlaceholderConfigurer placeholderConfigurerDev(ConfigurableEnvironment env) {
        final String fileName = "common.properties";
        Path resourceDirectory = Paths.get("src","main","resources", "properties");
        String absolutePath = resourceDirectory.toFile().getAbsolutePath();
        final File file = new File(absolutePath.concat("/").concat(fileName));
        if (file.exists()) {
            try {
                MutablePropertySources sources = env.getPropertySources();
                sources.addFirst(new PropertiesPropertySource(fileName, PropertiesLoaderUtils.loadAllProperties(file.getName())));
            } catch (Exception ex) {
                log.error(ex.getMessage(), ex);
                throw new RuntimeException(ex.getMessage(), ex);
            }
        }
        this.env = env;
        return new PropertySourcesPlaceholderConfigurer();
    }

Thanks to @Lemmy for the direction on how to solve this issue.

My final solution was to create a new common-test-context.xml file where I can look for the property file in the properties folder on the class path. I placed this file in src/test/resources/spring folder and imported the actual common-context.xml from src/main/resources/spring folder into it.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:batch="http://www.springframework.org/schema/batch"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans-2.5.xsd		
		http://www.springframework.org/schema/tx 
		http://www.springframework.org/schema/tx/spring-tx-2.5.xsd     	
     	http://www.springframework.org/schema/batch 
     	http://www.springframework.org/schema/batch/spring-batch.xsd
     	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

	<import resource="classpath*:/spring/common-context.xml" />
	
	
	<bean id="commonAppProperties"
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="ignoreResourceNotFound" value="true" />
		<property name="ignoreUnresolvablePlaceholders" value="true" />
		<property name="locations">
			<list>
				<value>classpath:/properties/common.properties</value>
			</list>
		</property>
	</bean>
	
</beans>