Override a single property for all tests

I have a set of properties in src/main/resources/application.properties:

app.firstprop=2
app.secondprop=3
app.thirdprop=5
app.fourthprop=7

And I want to override app.secondprop for all my tests, while keeping the remaining properties unchanged. One option is:

@SpringBootTest(properties=["app.secondprop=99"])

but that means I have to repeat this property value in every single test file.

Another option is to use src/test/resources/application.properties to override my properties file. Unfortunately, I have to specify all the unchanged properties as well as the overridden property:

app.firstprop=2
app.secondprop=99
app.thirdprop=5
app.fourthprop=7

If I don't specify the unchanged properties, they won't be defined during the tests. This again is unwanted repetition.

How do I override a single property for all tests and keep to the DRY principle?

If you want a specific property value in all your tests, then follow Andrew S's suggestion:

• override test props in application-test.properties (no need to specify all props)
• activate profile test via @ActiveProfiles("test")

If you want a specific property value in some tests, then use test class inheritance:

• create a parent test class, annotate it with @SpringBootTest(properties=["app.secondprop=99"])
• extend or implement this parent test class in test classes where you want to have the value.
  Also you are still can override this prop in child test classes.

@SpringBootTest(properties = {"app.secondprop=99"})
interface ParentTest {
}

class ChildTest implements ParentTest {

    @Value("${app.secondprop}")
    private String prop2nd;

    @Test
    void test() {
        assertEquals("99", prop2nd);
    }
}

// here you implement ParentTest, but overrides the prop's value
@SpringBootTest(properties = {"app.secondprop=199"})
class ChildTestWithOwnValue implements ParentTest {

    @Value("${app.secondprop}")
    private String prop2nd;

    @Test
    void test() {
        assertEquals("199", prop2nd);
    }
}