BAEL-4530: A Guide to @DynamicPropertySource in Spring (#9877)

* A Guide to @DynamicPropertySource in Spring

* Moving to a new module

* Reverting the Changes in the original module

testing-modules/spring-testing-2/src/test/java/com/baeldung/dynamicproperties/ArticleLiveTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.dynamicproperties;
+
+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;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringBootTest
+@Testcontainers
+@ActiveProfiles("pg")
+public class ArticleLiveTest {
+
+    @Container
+    static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:11")
+      .withDatabaseName("prop")
+      .withUsername("postgres")
+      .withPassword("pass")
+      .withExposedPorts(5432);
+
+    @Autowired
+    private ArticleRepository articleRepository;
+
+    @DynamicPropertySource
+    static void registerPgProperties(DynamicPropertyRegistry registry) {
+        registry.add("spring.datasource.url",
+          () -> String.format("jdbc:postgresql://localhost:%d/prop", postgres.getFirstMappedPort()));
+        registry.add("spring.datasource.username", () -> "postgres");
+        registry.add("spring.datasource.password", () -> "pass");
+    }
+
+    @Test
+    void givenAnArticle_whenPersisted_thenCanBeFoundInTheDb() {
+        Article article = new Article();
+        article.setTitle("A Guide to @DynamicPropertySource in Spring");
+        article.setContent("Today's applications...");
+
+        articleRepository.save(article);
+        Article persisted = articleRepository.findAll().get(0);
+        assertThat(persisted.getId()).isNotNull();
+        assertThat(persisted.getTitle()).isEqualTo("A Guide to @DynamicPropertySource in Spring");
+        assertThat(persisted.getContent()).isEqualTo("Today's applications...");
+    }
+}

testing-modules/spring-testing-2/src/test/java/com/baeldung/dynamicproperties/ArticleTestFixtureLiveTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.dynamicproperties;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ActiveProfiles;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringBootTest
+@ActiveProfiles("pg")
+@ExtendWith(PostgreSQLExtension.class)
+public class ArticleTestFixtureLiveTest {
+
+    @Autowired
+    private ArticleRepository articleRepository;
+
+    @Test
+    void givenAnArticle_whenPersisted_thenShouldBeAbleToReadIt() {
+        Article article = new Article();
+        article.setTitle("A Guide to @DynamicPropertySource in Spring");
+        article.setContent("Today's applications...");
+
+        articleRepository.save(article);
+        Article persisted = articleRepository.findAll().get(0);
+        assertThat(persisted.getId()).isNotNull();
+        assertThat(persisted.getTitle()).isEqualTo("A Guide to @DynamicPropertySource in Spring");
+        assertThat(persisted.getContent()).isEqualTo("Today's applications...");
+    }
+}

testing-modules/spring-testing-2/src/test/java/com/baeldung/dynamicproperties/ArticleTraditionalLiveTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.dynamicproperties;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.ContextConfiguration;
+import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringBootTest
+@Testcontainers
+@ActiveProfiles("pg")
+@ContextConfiguration(initializers = ArticleTraditionalLiveTest.EnvInitializer.class)
+class ArticleTraditionalLiveTest {
+
+    @Container
+    static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:11")
+      .withDatabaseName("prop")
+      .withUsername("postgres")
+      .withPassword("pass")
+      .withExposedPorts(5432);
+
+    static class EnvInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
+
+        @Override
+        public void initialize(ConfigurableApplicationContext applicationContext) {
+            TestPropertyValues.of(
+              String.format("spring.datasource.url=jdbc:postgresql://localhost:%d/prop", postgres.getFirstMappedPort()),
+              "spring.datasource.username=postgres",
+              "spring.datasource.password=pass"
+            ).applyTo(applicationContext);
+        }
+    }
+
+    @Autowired
+    private ArticleRepository articleRepository;
+
+    @Test
+    void givenAnArticle_whenPersisted_thenShouldBeAbleToReadIt() {
+        Article article = new Article();
+        article.setTitle("A Guide to @DynamicPropertySource in Spring");
+        article.setContent("Today's applications...");
+
+        articleRepository.save(article);
+        Article persisted = articleRepository.findAll().get(0);
+        assertThat(persisted.getId()).isNotNull();
+        assertThat(persisted.getTitle()).isEqualTo("A Guide to @DynamicPropertySource in Spring");
+        assertThat(persisted.getContent()).isEqualTo("Today's applications...");
+    }
+}

testing-modules/spring-testing-2/src/test/java/com/baeldung/dynamicproperties/PostgreSQLExtension.java

@@ -0,0 +1,31 @@
+package com.baeldung.dynamicproperties;
+
+import org.junit.jupiter.api.extension.AfterAllCallback;
+import org.junit.jupiter.api.extension.BeforeAllCallback;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.testcontainers.containers.PostgreSQLContainer;
+
+public class PostgreSQLExtension implements BeforeAllCallback, AfterAllCallback {
+
+    private PostgreSQLContainer<?> postgres;
+
+    @Override
+    public void beforeAll(ExtensionContext context) {
+        postgres = new PostgreSQLContainer<>("postgres:11")
+          .withDatabaseName("prop")
+          .withUsername("postgres")
+          .withPassword("pass")
+          .withExposedPorts(5432);
+
+        postgres.start();
+        String jdbcUrl = String.format("jdbc:postgresql://localhost:%d/prop", postgres.getFirstMappedPort());
+        System.setProperty("spring.datasource.url", jdbcUrl);
+        System.setProperty("spring.datasource.username", "postgres");
+        System.setProperty("spring.datasource.password", "pass");
+    }
+
+    @Override
+    public void afterAll(ExtensionContext context) {
+        postgres.stop();
+    }
+}