Test profiles and configuration in Spring Boot - Step-by-Step Execution

Concept Flow - Test profiles and configuration

Start Application

↓

Check Active Profile

↓

Load application-{profile}.properties

↓

Override default config

↓

Run Tests with Profile

↓

Use Profile-specific Beans

↓

Tests Execute with Configured Settings

↓

End

The application starts, checks which profile is active, loads the matching configuration, overrides defaults, and runs tests using those settings.

Execution Sample

Spring Boot

@SpringBootTest
@ActiveProfiles("test")
class MyServiceTest {
  @Autowired
  MyService service;
  @Test
  void testMethod() {
    assertEquals("testValue", service.getConfigValue());
  }
}

This test runs with the 'test' profile active, so it uses test-specific configuration values.

Execution Table

Step	Action	Profile Active	Config Loaded	Bean Used	Test Output
1	Start Application	none	application.properties	default beans	N/A
2	Activate 'test' profile	test	application-test.properties	test beans if any	N/A
3	Load Configurations	test	Defaults overridden by test config	test beans	N/A
4	Run testMethod()	test	application-test.properties	test beans	service.getConfigValue() returns 'testValue'
5	Assert result	test	application-test.properties	test beans	Pass: 'testValue' matches expected
6	End Test	test	application-test.properties	test beans	Test completes successfully

💡 Test finishes after asserting the expected value with the test profile configuration.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
activeProfile	none	test	test	test	test
configSource	application.properties	application-test.properties	application-test.properties	application-test.properties	application-test.properties
beanType	default	test	test	test	test
service.getConfigValue()	N/A	N/A	N/A	testValue	testValue

Key Moments - 2 Insights

Why does the test use 'application-test.properties' instead of 'application.properties'?

Because the '@ActiveProfiles("test")' annotation activates the 'test' profile, causing Spring Boot to load 'application-test.properties' which overrides the default config as shown in execution_table step 2 and 3.

How does Spring Boot know which beans to use for the test profile?

Spring Boot loads beans annotated or configured for the active profile. In the execution_table steps 3 and 4, 'test beans' are used instead of default beans because the 'test' profile is active.

Visual Quiz - 3 Questions

Look at the execution_table at step 4, what value does 'service.getConfigValue()' return?

A "null"

B "testValue"

C "defaultValue"

D "productionValue"

💡 Hint

Check the 'Test Output' column at step 4 in the execution_table.

At which step does the application load the profile-specific configuration?

A Step 3

B Step 1

C Step 2

D Step 5

💡 Hint

Look at the 'Config Loaded' column in the execution_table to find when overrides happen.

If the '@ActiveProfiles' annotation was removed, what would change in the variable_tracker?

A beanType would be 'test'

B activeProfile would remain 'test'

C configSource would be 'application.properties'

D service.getConfigValue() would return 'testValue'

💡 Hint

Refer to the 'activeProfile' and 'configSource' rows in variable_tracker to see what changes without profile activation.

Concept Snapshot

Test Profiles and Configuration in Spring Boot:
- Use @ActiveProfiles("profileName") to activate a profile in tests.
- Spring Boot loads application-{profile}.properties overriding defaults.
- Beans and configs change based on active profile.
- Tests run with profile-specific settings for isolation.
- Helps separate dev, test, prod configs cleanly.

Full Transcript

In Spring Boot, test profiles let you run tests with special settings. When the application starts, it checks which profile is active. If the 'test' profile is active, it loads 'application-test.properties' to override default settings. Beans specific to the test profile are used. This way, tests run with configurations made just for testing. The example code shows a test class with '@ActiveProfiles("test")' which activates the test profile. The execution table traces how the profile activates, config files load, beans switch, and the test method returns the expected test value. Variables like activeProfile and configSource change to reflect the test profile. This helps keep test settings separate from production or development. Understanding when and how profiles load helps avoid confusion about which configs and beans are used during tests.