GH-466 - Allow using ApplicationModuleTest outside of module package

spring-modulith-examples/spring-modulith-example-full/src/test/java/otherpackage/integration/OrderIntegrationTests.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2022-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package otherpackage.integration;
+
+import example.order.Order;
+import example.order.OrderManagement;
+import lombok.RequiredArgsConstructor;
+import org.junit.jupiter.api.Test;
+import org.springframework.modulith.test.ApplicationModuleTest;
+
+/**
+ * Test to showcase {@link ApplicationModuleTest} outside of a module package
+ */
+@ApplicationModuleTest(module = "order", classes = {example.Application.class})
+@RequiredArgsConstructor
+class OrderIntegrationTests {
+
+	private final OrderManagement orders;
+
+	@Test
+	void completesOrder() {
+		orders.complete(new Order());
+	}
+}

spring-modulith-test/src/main/java/org/springframework/modulith/test/ApplicationModuleTest.java

@@ -76,6 +76,14 @@
 	 */
 	String[] extraIncludes() default {};
 
+	/**
+	 * Logical name of the module in case {@link ApplicationModuleTest} will be used outside a module package
+	 */
+	String module() default "";
+
+	@AliasFor(annotation = SpringBootTest.class)
+	Class<?>[] classes() default {};
+
 	/**
 	 * The type of web environment to create when applicable. Defaults to {@link WebEnvironment#MOCK}.
 	 *

spring-modulith-test/src/main/java/org/springframework/modulith/test/ModuleTestExecution.java

@@ -34,6 +34,7 @@
 import org.springframework.modulith.core.ApplicationModules;
 import org.springframework.modulith.core.JavaPackage;
 import org.springframework.modulith.test.ApplicationModuleTest.BootstrapMode;
+import org.springframework.util.StringUtils;
 import org.springframework.util.function.SingletonSupplier;
 
 /**
@@ -94,12 +95,21 @@ public static Supplier<ModuleTestExecution> of(Class<?> type) {
 
 			var annotation = AnnotatedElementUtils.findMergedAnnotation(type, ApplicationModuleTest.class);
 			var packageName = type.getPackage().getName();
+			var optionalModulithType = findSpringBootApplicationByClasses(annotation);
 
-			var modulithType = MODULITH_TYPES.computeIfAbsent(type,
-					it -> new AnnotatedClassFinder(SpringBootApplication.class).findFromPackage(packageName));
+			var modulithType = optionalModulithType.orElseGet(() -> MODULITH_TYPES.computeIfAbsent(type,
+					it -> new AnnotatedClassFinder(SpringBootApplication.class).findFromPackage(packageName)));
 			var modules = ApplicationModules.of(modulithType);
-			var module = modules.getModuleForPackage(packageName).orElseThrow( //
+
+			var moduleName = annotation.module();
+			ApplicationModule module;
+			if (StringUtils.hasText(moduleName)) {
+				module = modules.getModuleByName(moduleName).orElseThrow( //
+					() -> new IllegalStateException(String.format("Unable to find module %s!", moduleName)));
+			} else {
+				module = modules.getModuleForPackage(packageName).orElseThrow( //
 					() -> new IllegalStateException(String.format("Package %s is not part of any module!", packageName)));
+			}
 
 			return EXECUTIONS.computeIfAbsent(new Key(module.getBasePackage().getName(), annotation),
 					it -> new ModuleTestExecution(annotation, modules, module));
@@ -230,5 +240,16 @@ private static Stream<ApplicationModule> getExtraModules(ApplicationModuleTest a
 				.flatMap(Optional::stream);
 	}
 
+	private static Optional<Class<?>> findSpringBootApplicationByClasses(ApplicationModuleTest annotation) {
+		for (Class<?> clazz : annotation.classes()) {
+			Class<?> modulithType = MODULITH_TYPES.computeIfAbsent(clazz,
+					it -> new AnnotatedClassFinder(SpringBootApplication.class).findFromPackage(clazz.getPackageName()));
+			if (modulithType != null) {
+				return Optional.of(modulithType);
+			}
+		}
+		return Optional.empty();
+	}
+
 	private static record Key(String moduleBasePackage, ApplicationModuleTest annotation) {}
 }