Overriding Properties in @SpringBootTest

Direct Answer

Use @SpringBootTest(properties = ...) for inline test properties, @TestPropertySource for declared test sources, @ActiveProfiles("test") to activate profile-specific configuration, or @DynamicPropertySource for values created at test time. Spring has a defined property-source precedence, so use the mechanism whose scope and precedence match the test instead of assuming every test source is equivalent.

Code Example

@SpringBootTest(properties = {
    "spring.datasource.url=jdbc:h2:mem:testdb",
    "app.feature.notifications=false"
})
class OrderServiceTest {
    @Autowired private OrderService orderService;

    @Test
    void testOrderCreation() {
        // H2 in-memory DB and notifications disabled for this test class
    }
}

@SpringBootTest
@TestPropertySource(properties = {
    "server.port=0",                       // random port
    "app.external.api=http://localhost:8081"
})
class PaymentControllerTest {
    // @TestPropertySource has higher precedence than the properties attribute
}

@SpringBootTest
@ActiveProfiles("test")
class UserRepositoryTest {
    // loads application-test.yml automatically
}

Common Mistakes & Pitfalls

• Duplicating all production configuration: Override only what the test intentionally changes.
• Assuming braces are mandatory: Java permits the single-element shorthand for an array-valued annotation attribute, so both properties = "a=b" and properties = {"a=b"} are valid.
• Setting one key in several test sources: Even when precedence is documented, the result is harder to understand and cache reuse may change. Keep one obvious owner.
• Hardcoding runtime ports: Register container-generated values with @DynamicPropertySource.