Spring Boot单元测试：ApplicationRunner Bean加载异常与@ConditionalOnProperty配置问题

Hey there! Let's tackle these two Spring Boot unit testing issues one by one with practical solutions:

1. How to Load Configuration with @ConditionalOnProperty in Unit Tests #

Your CrawlerConfiguration combines both @ConditionalOnProperty and @Profile annotations, so we need to satisfy both conditions in your test setup. Here's how to make sure the configuration loads correctly:

• First, set the required property batch=Crawler to activate the configuration class. You can do this via @TestPropertySource or directly in @SpringBootTest.
• Second, activate the target profile (test or production) using @ActiveProfiles to get the right Crawler bean.

Sample Test Class for CrawlerConfiguration #

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ActiveProfiles;

@SpringBootTest(properties = {"batch=Crawler"})
@ActiveProfiles("test")
public class CrawlerConfigurationTest {

    @Autowired
    private Crawler crawler;

    @Test
    void testTestCrawlerBeanLoaded() {
        // Verify we're using the test-specific crawler (adjust based on your Crawler's methods)
        assert !crawler.isProductionMode();
        assert crawler.getName().equals("TestCrawler");
    }
}

Lightweight Test (Without Full Context) #

If you don't need the full Spring Boot context, use @SpringJUnitConfig to load only the necessary components:

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.TestPropertySource;
import org.springframework.context.annotation.Import;

@SpringJUnitConfig
@ActiveProfiles("test")
@TestPropertySource(properties = {"batch=Crawler", "name=TestCrawler"})
@Import(CrawlerConfiguration.class)
public class CrawlerConfigurationLightTest {

    @Autowired
    private Crawler crawler;

    @Test
    void testCrawlerInjection() {
        assert crawler != null;
        assert crawler.getName().equals("TestCrawler");
    }
}

2. Fixing Bean Definition Issues in ApplicationRunner Unit Tests #

The main pain points here are either the runner executing unexpectedly during test setup, or the context failing to load the correct beans. Here are two reliable approaches:

Option 1: Test Runner Logic in Isolation #

Extract the core logic of your ApplicationRunner into a separate component, then mock dependencies and test it directly (no full context needed):

import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.boot.ApplicationArguments;

@ExtendWith(MockitoExtension.class)
public class MyApplicationRunnerTest {

    @Mock
    private ApplicationArguments args;

    @Mock
    private Crawler crawler; // Mock the dependency your runner uses

    @Test
    void testRunnerBusinessLogic() {
        MyApplicationRunner runner = new MyApplicationRunner(crawler);
        runner.run(args);

        // Verify interactions (adjust based on your runner's behavior)
        // Mockito.verify(crawler).startCrawling();
    }
}

Option 2: Load Full Context but Control Runner Execution #

If you need the full context but don't want the runner to run automatically, use @MockBean to replace the actual runner:

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.TestPropertySource;
import org.springframework.beans.factory.annotation.Autowired;

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
@ActiveProfiles("test")
@TestPropertySource(properties = {"batch=Crawler", "name=TestCrawler"})
public class ApplicationRunnerContextTest {

    @MockBean
    private MyApplicationRunner applicationRunner; // Prevents actual runner from executing

    @Autowired
    private Crawler crawler;

    @Test
    void testCorrectBeanLoaded() {
        // Verify the crawler bean is properly injected
        assert crawler != null;
        assert !crawler.isProductionMode();
    }
}

If you want to test the runner's full behavior in context, remove the @MockBean and add assertions based on the runner's side effects (e.g., database updates, log entries).

内容的提问来源于stack exchange，提问作者Tsuyoshi