Spring Testing - @TestPropertySource default properties file detection

This example demonstrates how to use an implicit properties location for @TestPropertySource. If @TestPropertySource is declared as an empty annotation (i.e., without explicit values for the locations or properties attributes), an attempt will be made to detect a default properties file (on the classpath) relative to the class that declares the annotation.

Example

Creating a Spring application

@Service
public class ReportService {
  @Value("${report-subscriber:admin@example.com}")
  private String theSubscriber;

  public String getReportSubscriber() {
      return theSubscriber;
  }
}

src/main/resources/prod.properties

report-subscriber=theManager@example.com

src/main/resources/test.properties

report-subscriber=theDeveloper@example.com

@PropertySource("classpath:prod.properties")
@Configuration
@ComponentScan
public class AppConfig {
  @Bean
  public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() {
      return new PropertySourcesPlaceholderConfigurer();
  }

  public static void main(String[] args) {
      AnnotationConfigApplicationContext context =
              new AnnotationConfigApplicationContext(AppConfig.class);
      ReportService rs = context.getBean(ReportService.class);
      System.out.println(rs.getReportSubscriber());
  }
}

Running above class:

Output

theManager@example.com

The default properties file

src/test/resources/com/logicbig/example/ReportServiceTests.properties

report-subscriber=theTester@example.com

The JUnit test

We are not going to specify 'locations' or 'properties' attribute with @TestPropertySource:

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = AppConfig.class)
@TestPropertySource
public class ReportServiceTests {
  @Autowired
  private ReportService reportService;

  @Test
  public void testReportSubscriber() {
      String s = reportService.getReportSubscriber();
      System.out.println(s);
      Assert.assertEquals("theTester@example.com", s);
  }
}

mvn  -q test -Dtest=ReportServiceTests

Output

D:\example-projects\spring-core-testing\test-property-source-with-default-location>mvn  -q test -Dtest=ReportServiceTests

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.logicbig.example.ReportServiceTests
theTester@example.com
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.41 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

INFO: Detected default properties file "classpath:com/logicbig/example/ReportServiceTests.properties" for test class [com.logicbig.example.ReportServiceTests]

Example Project

Dependencies and Technologies Used:

• spring-context 4.3.8.RELEASE: Spring Context.
• spring-test 4.3.9.RELEASE: Spring TestContext Framework.
• junit 4.12: JUnit is a unit testing framework for Java, created by Erich Gamma and Kent Beck.
• JDK 1.8
• Maven 3.3.9