#29 improve support for Spring Boot's test annotations

Author: tomix26

README.md

@@ -120,14 +120,14 @@ public class FlywayMigrationIntegrationTest {
 
 Spring Boot provides several annotations to simplify writing integration tests.
 One of them is the `@DataJpaTest` annotation, which can be used when a test focuses only on JPA components.
-By default, tests annotated with `@DataJpaTest` will use an embedded in-memory database. **This in-memory database can be H2, Derby or HSQL, but not the PostgreSQL database**.
-To change that, you must first disable the default in-memory database by `@AutoConfigureTestDatabase(replace = NONE)` and enable PostgreSQL database by `@AutoConfigureEmbeddedDatabase` instead. 
+By default, tests annotated with this annotation use an in-memory database.
+But if the `@DataJpaTest` annotation is used together with the `@AutoConfigureEmbeddedDatabase` annotation,
+the in-memory database is automatically disabled and replaced by an embedded postgres database. 
 
 ```java
 @RunWith(SpringRunner.class)
-@AutoConfigureTestDatabase(replace = NONE)
-@AutoConfigureEmbeddedDatabase
 @DataJpaTest
+@AutoConfigureEmbeddedDatabase
 public class SpringDataJpaAnnotationTest {
     // class body...
 }
@@ -142,9 +142,8 @@ You can also consider creating a custom [composed annotation](https://github.com
   @Inherited
   @Target(ElementType.TYPE)
   @Retention(RetentionPolicy.RUNTIME)
-  @AutoConfigureTestDatabase(replace = Replace.NONE)
-  @AutoConfigureEmbeddedDatabase
   @DataJpaTest
+  @AutoConfigureEmbeddedDatabase
   public @interface PostgresDataJpaTest {
 
       @AliasFor(annotation = DataJpaTest.class)

embedded-database-spring-test/src/main/java/io/zonky/test/db/postgres/EmbeddedPostgresContextCustomizerFactory.java

@@ -16,6 +16,7 @@
 
 package io.zonky.test.db.postgres;
 
+import com.google.common.collect.ImmutableMap;
 import io.zonky.test.db.AutoConfigureEmbeddedDatabase;
 import io.zonky.test.db.AutoConfigureEmbeddedDatabase.EmbeddedDatabaseType;
 import io.zonky.test.db.AutoConfigureEmbeddedDatabase.Replace;
@@ -39,6 +40,8 @@
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
 import org.springframework.test.context.ContextConfigurationAttributes;
 import org.springframework.test.context.ContextCustomizer;
 import org.springframework.test.context.ContextCustomizerFactory;
@@ -86,6 +89,8 @@ public PreloadableEmbeddedPostgresContextCustomizer(AutoConfigureEmbeddedDatabas
 
         @Override
         public void customizeContext(ConfigurableApplicationContext context, MergedContextConfiguration mergedConfig) {
+            context.addBeanFactoryPostProcessor(new EnvironmentPostProcessor(context.getEnvironment()));
+
             Class<?> testClass = mergedConfig.getTestClass();
             FlywayTest[] flywayAnnotations = findFlywayTestAnnotations(testClass);
 
@@ -118,6 +123,27 @@ public int hashCode() {
         }
     }
 
+    protected static class EnvironmentPostProcessor implements BeanDefinitionRegistryPostProcessor {
+
+        private final ConfigurableEnvironment environment;
+
+        public EnvironmentPostProcessor(ConfigurableEnvironment environment) {
+            this.environment = environment;
+        }
+
+        @Override
+        public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
+            environment.getPropertySources().addFirst(new MapPropertySource(
+                    PreloadableEmbeddedPostgresContextCustomizer.class.getSimpleName(),
+                    ImmutableMap.of("spring.test.database.replace", "NONE")));
+        }
+
+        @Override
+        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
+            // nothing to do
+        }
+    }
+
     protected static class PreloadableEmbeddedPostgresRegistrar implements BeanDefinitionRegistryPostProcessor {
 
         private final AutoConfigureEmbeddedDatabase databaseAnnotation;