feat: add spring-boot-testing skill for Spring Boot 4.0 (#1085)

- Introduced MockMvcTester for AssertJ-style assertions in Spring MVC testing. - Added @RestClientTest for testing REST clients with MockRestServiceServer. - Implemented RestTestClient as a modern alternative to TestRestTemplate. - Documented migration steps from Spring Boot 3.x to 4.0, including dependency and annotation changes. - Created an overview of test slices to guide testing strategies. - Included Testcontainers setup for JDBC testing with PostgreSQL and MySQL. - Enhanced @WebMvcTest documentation with examples for various HTTP methods and validation.
2026-03-20 16:15:12 +00:00 · 2026-03-20 04:54:37 +05:30
parent ee71c0689c
commit e4fc57f204
16 changed files with 3171 additions and 0 deletions
--- a/skills/spring-boot-testing/references/testcontainers-jdbc.md
+++ b/skills/spring-boot-testing/references/testcontainers-jdbc.md
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+# Testcontainers JDBC
+
+Testing JPA repositories with real databases using Testcontainers.
+
+## Overview
+
+Testcontainers provides real database instances in Docker containers for integration testing. More reliable than H2 for production parity.
+
+## PostgreSQL Setup
+
+### Dependencies
+
+```xml
+<dependency>
+  <groupId>org.springframework.boot</groupId>
+  <artifactId>spring-boot-testcontainers</artifactId>
+  <scope>test</scope>
+</dependency>
+<dependency>
+  <groupId>org.testcontainers</groupId>
+  <artifactId>testcontainers-postgresql</artifactId>
+  <scope>test</scope>
+</dependency>
+```
+
+### Basic Test
+
+```java
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@Testcontainers
+class OrderRepositoryPostgresTest {
+  
+  @Container
+  @ServiceConnection
+  static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18");
+  
+  @Autowired
+  private OrderRepository orderRepository;
+  
+  @Autowired
+  private TestEntityManager entityManager;
+}
+```
+
+## MySQL Setup
+
+```xml
+<dependency>
+  <groupId>org.testcontainers</groupId>
+  <artifactId>testcontainers-mysql</artifactId>
+  <scope>test</scope>
+</dependency>
+```
+
+```java
+@Container
+@ServiceConnection
+static MySQLContainer<?> mysql = new MySQLContainer<>("mysql:8.4");
+```
+
+## Multiple Databases
+
+```java
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@Testcontainers
+class MultiDatabaseTest {
+  
+  @Container
+  @ServiceConnection(name = "primary")
+  static PostgreSQLContainer<?> primaryDb = new PostgreSQLContainer<>("postgres:18");
+  
+  @Container
+  @ServiceConnection(name = "analytics")
+  static PostgreSQLContainer<?> analyticsDb = new PostgreSQLContainer<>("postgres:18");
+}
+```
+
+## Container Reuse (Speed Optimization)
+
+Add to `~/.testcontainers.properties`:
+
+```properties
+testcontainers.reuse.enable=true
+```
+
+Then enable reuse in code:
+
+```java
+@Container
+@ServiceConnection
+static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18")
+  .withReuse(true);
+```
+
+## Database Initialization
+
+### With SQL Scripts
+
+```java
+@Container
+@ServiceConnection
+static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18")
+  .withInitScript("schema.sql");
+```
+
+### With Flyway
+
+```java
+@SpringBootTest
+@Testcontainers
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+class MigrationTest {
+  
+  @Container
+  @ServiceConnection
+  static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18");
+  
+  @Autowired
+  private Flyway flyway;
+  
+  @Test
+  void shouldApplyMigrations() {
+    flyway.migrate();
+    // Test code
+  }
+}
+```
+
+## Advanced Configuration
+
+### Custom Database/Schema
+
+```java
+@Container
+@ServiceConnection
+static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18")
+  .withDatabaseName("testdb")
+  .withUsername("testuser")
+  .withPassword("testpass")
+  .withInitScript("init-schema.sql");
+```
+
+### Wait Strategies
+
+```java
+@Container
+static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18")
+  .waitingFor(Wait.forLogMessage(".*database system is ready.*", 1));
+```
+
+## Test Example
+
+```java
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@Testcontainers
+class OrderRepositoryTest {
+  
+  @Container
+  @ServiceConnection
+  static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18");
+  
+  @Autowired
+  private OrderRepository orderRepository;
+  
+  @Autowired
+  private TestEntityManager entityManager;
+  
+  @Test
+  void shouldFindOrdersByStatus() {
+    // Given
+    entityManager.persist(new Order("PENDING"));
+    entityManager.persist(new Order("COMPLETED"));
+    entityManager.flush();
+    
+    // When
+    List<Order> pending = orderRepository.findByStatus("PENDING");
+    
+    // Then
+    assertThat(pending).hasSize(1);
+    assertThat(pending.get(0).getStatus()).isEqualTo("PENDING");
+  }
+  
+  @Test
+  void shouldSupportPostgresSpecificFeatures() {
+    // Can use Postgres-specific features like:
+    // - JSONB columns
+    // - Array types
+    // - Full-text search
+  }
+}
+```
+
+## @DynamicPropertySource Alternative
+
+If not using @ServiceConnection:
+
+```java
+@SpringBootTest
+@Testcontainers
+class OrderServiceTest {
+  
+  @Container
+  static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:18");
+  
+  @DynamicPropertySource
+  static void configureProperties(DynamicPropertyRegistry registry) {
+    registry.add("spring.datasource.url", postgres::getJdbcUrl);
+    registry.add("spring.datasource.username", postgres::getUsername);
+    registry.add("spring.datasource.password", postgres::getPassword);
+  }
+}
+```
+
+## Supported Databases
+
+| Database | Container Class | Maven Artifact |
+| -------- | --------------- | -------------- |
+| PostgreSQL | PostgreSQLContainer | testcontainers-postgresql |
+| MySQL | MySQLContainer | testcontainers-mysql |
+| MariaDB | MariaDBContainer | testcontainers-mariadb |
+| SQL Server | MSSQLServerContainer | testcontainers-mssqlserver |
+| Oracle | OracleContainer | testcontainers-oracle-free |
+| MongoDB | MongoDBContainer | testcontainers-mongodb |
+
+## Best Practices
+
+1. Use @ServiceConnection when possible (Spring Boot 3.1+)
+2. Enable container reuse for faster local builds
+3. Use specific versions (postgres:18) not latest
+4. Keep container config in static field
+5. Use @DataJpaTest with AutoConfigureTestDatabase.Replace.NONE