Test profiles and configuration in Spring Boot

Introduction

Test profiles let you run your Spring Boot app with special settings just for testing. This helps keep tests separate from real app settings.

You want to use a different database for testing than for real use.

You need to change some app settings only when running tests.

You want to avoid sending real emails during tests.

You want to speed up tests by disabling slow features.

You want to isolate test data from production data.

Syntax

Spring Boot

spring.profiles.active=test

# application-test.properties
spring.datasource.url=jdbc:h2:mem:testdb
spring.jpa.hibernate.ddl-auto=create-drop

Use spring.profiles.active to select which profile to run.

Create separate application-{profile}.properties files for each profile.

Examples

This sets the active profile to dev and changes logging level only for that profile.

Spring Boot

# application.properties
spring.profiles.active=dev

# application-dev.properties
logging.level.root=DEBUG

This annotation tells Spring Boot to use the test profile when running this test class.

Spring Boot

@ActiveProfiles("test")
@SpringBootTest
public class MyServiceTest {

}

Overrides mail server settings only for the test profile to avoid sending real emails.

Spring Boot

# application-test.properties
spring.mail.host=localhost
spring.mail.port=2525

Sample Program

This Spring Boot app returns a message from configuration. When run with the test profile active, it shows the test message. Otherwise, it shows the default message.

Spring Boot

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

@RestController
class ProfileController {

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

    @GetMapping("/message")
    public String getMessage() {
        return message;
    }
}

// application.properties
// app.message=Hello from default profile

// application-test.properties
// app.message=Hello from test profile

Important Notes

Activate profiles in application.properties or via command line with --spring.profiles.active=test.

Use @ActiveProfiles in tests to specify which profile to use.

Keep test configurations simple and isolated to avoid affecting real app behavior.

Summary

Test profiles let you run your app with special settings just for tests.

Use application-{profile}.properties files to separate settings.

Activate profiles via config files, command line, or annotations in tests.

Practice

1. What is the main purpose of using test profiles in a Spring Boot application?

easy

A. To run the application with special settings only during testing

B. To improve the application's runtime performance in production

C. To automatically generate test data for the application

D. To disable security features permanently

Solution

1. Step 1: Understand test profiles concept

   Test profiles allow running the app with different settings specifically for testing purposes.

2. Step 2: Compare options

   Only To run the application with special settings only during testing correctly describes the purpose of test profiles as special settings for tests.

3. Final Answer:

   To run the application with special settings only during testing -> Option A

4. Quick Check:

   Test profiles = special test settings [OK]

Hint: Test profiles isolate test settings from production [OK]

Common Mistakes:

• Confusing test profiles with performance tuning
• Thinking test profiles generate test data automatically
• Assuming test profiles disable security permanently

2. Which of the following is the correct way to name a properties file for a test profile named testdb?

easy

A. application.properties.testdb

B. testdb-application.properties

C. application-testdb.properties

D. application_testdb.properties

Solution

1. Step 1: Recall Spring Boot profile file naming

   Spring Boot uses the pattern application-{profile}.properties for profile-specific config files.

2. Step 2: Match the pattern with the profile name

   For profile testdb, the correct file name is application-testdb.properties.

3. Final Answer:

   application-testdb.properties -> Option C

4. Quick Check:

   Profile file = application-{profile}.properties [OK]

Hint: Use application-{profile}.properties naming [OK]

Common Mistakes:

• Placing profile name after .properties
• Using underscores instead of hyphens
• Reversing the order of profile and application

3. Given the following test class annotation:
@ActiveProfiles("test")
and two property files:
application.properties with db.url=prod-db
application-test.properties with db.url=test-db
What will be the value of db.url during this test?

medium

A. prod-db

B. test-db

C. null

D. application.properties

Solution

1. Step 1: Understand @ActiveProfiles effect

   @ActiveProfiles("test") activates the 'test' profile for the test run.

2. Step 2: Determine property file precedence

   Properties in application-test.properties override those in application.properties when 'test' profile is active.

3. Final Answer:

   test-db -> Option B

4. Quick Check:

   Active profile properties override default [OK]

Hint: Active profile properties override defaults [OK]

Common Mistakes:

• Assuming default properties always apply
• Confusing profile name in annotation
• Expecting null if profile is active

4. You have a test annotated with @ActiveProfiles("dev") but the test still uses properties from application.properties instead of application-dev.properties. What is the most likely cause?

medium

A. The test class must extend a special base class to use profiles

B. The @ActiveProfiles annotation is only for production

C. Spring Boot does not support multiple profiles

D. The application-dev.properties file is missing or misnamed

Solution

1. Step 1: Check profile file presence

   If application-dev.properties is missing or named incorrectly, Spring Boot falls back to application.properties.

2. Step 2: Verify annotation usage

   @ActiveProfiles works for tests to activate profiles; it is not limited to production.

3. Final Answer:

   The application-dev.properties file is missing or misnamed -> Option D

4. Quick Check:

   Missing profile file causes fallback to default [OK]

Hint: Check profile file name and location first [OK]

Common Mistakes:

• Thinking @ActiveProfiles is ignored in tests
• Believing Spring Boot lacks profile support
• Assuming inheritance is required for profiles

5. You want to run integration tests with a profile integration that uses a different database URL and disables security. Which combination correctly activates this profile and overrides the default settings?

hard

A. Create application-integration.properties with overrides and annotate tests with @ActiveProfiles("integration")

B. Add spring.profiles.active=integration only in application.properties

C. Use @Profile("integration") on the test class without any properties file

D. Set environment variable SPRING_PROFILE=integration but keep default properties unchanged

Solution

1. Step 1: Use profile-specific properties file

   Create application-integration.properties to override database URL and security settings for the integration profile.

2. Step 2: Activate profile in tests

   Annotate tests with @ActiveProfiles("integration") to activate the profile during test runs.

3. Final Answer:

   Create application-integration.properties with overrides and annotate tests with @ActiveProfiles("integration") -> Option A

4. Quick Check:

   Profile file + @ActiveProfiles activates test config [OK]

Hint: Use profile file plus @ActiveProfiles to activate [OK]

Common Mistakes:

• Setting active profile only in default properties
• Using @Profile instead of @ActiveProfiles on tests
• Relying on environment variable without config changes