How to set environment variable or system property in spring tests?

You can initialize the System property in a static initializer:

@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(locations = "classpath:whereever/context.xml")public class TestWarSpringContext {    static {        System.setProperty("myproperty", "foo");    }}

The static initializer code will be executed before the spring application context is initialized.

The right way to do this, starting with Spring 4.1, is to use a @TestPropertySource annotation.

@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(locations = "classpath:whereever/context.xml")@TestPropertySource(properties = {"myproperty = foo"})public class TestWarSpringContext {    ...    }

See @TestPropertySource in the Spring docs and Javadocs.

One can also use a test ApplicationContextInitializer to initialize a system property:

public class TestApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext>{    @Override    public void initialize(ConfigurableApplicationContext applicationContext)    {        System.setProperty("myproperty", "value");    }}

and then configure it on the test class in addition to the Spring context config file locations:

@ContextConfiguration(initializers = TestApplicationContextInitializer.class, locations = "classpath:whereever/context.xml", ...)@RunWith(SpringJUnit4ClassRunner.class)public class SomeTest{...}

This way code duplication can be avoided if a certain system property should be set for all the unit tests.