Support multi-view rendering

See gh-33162

spring-webmvc/src/test/java/org/springframework/web/servlet/view/FragmentsViewTests.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2002-2024 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 org.springframework.web.servlet.view;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledForJreRange;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.ResourceBundleMessageSource;
+import org.springframework.web.servlet.ModelAndView;
+import org.springframework.web.servlet.view.script.ScriptTemplateConfigurer;
+import org.springframework.web.servlet.view.script.ScriptTemplateViewResolver;
+import org.springframework.web.testfixture.servlet.MockHttpServletRequest;
+import org.springframework.web.testfixture.servlet.MockHttpServletResponse;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.condition.JRE.JAVA_21;
+
+/**
+ * Tests for rendering through {@link FragmentsView}.
+ *
+ * @author Rossen Stoyanchev
+ */
+@DisabledForJreRange(min = JAVA_21, disabledReason = "Kotlin doesn't support Java 21+ yet")
+public class FragmentsViewTests {
+
+
+	@Test
+	void render() throws Exception {
+
+		AnnotationConfigApplicationContext context =
+				new AnnotationConfigApplicationContext(ScriptTemplatingConfiguration.class);
+
+		String prefix = "org/springframework/web/servlet/view/script/kotlin/";
+		ScriptTemplateViewResolver viewResolver = new ScriptTemplateViewResolver(prefix, ".kts");
+		viewResolver.setApplicationContext(context);
+
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		FragmentsView view = FragmentsView.create(List.of(
+				new ModelAndView("fragment1", Map.of("foo", "Foo")),
+				new ModelAndView("fragment2", Map.of("bar", "Bar"))));
+
+		view.resolveNestedViews(viewResolver, Locale.ENGLISH);
+		view.render(Collections.emptyMap(), request, response);
+
+		assertThat(response.getContentAsString()).isEqualTo("<p>Hello Foo</p><p>Hello Bar</p>");
+	}
+
+
+	@Configuration
+	static class ScriptTemplatingConfiguration {
+
+		@Bean
+		ScriptTemplateConfigurer kotlinScriptConfigurer() {
+			ScriptTemplateConfigurer configurer = new ScriptTemplateConfigurer();
+			configurer.setEngineName("kotlin");
+			configurer.setScripts("org/springframework/web/servlet/view/script/kotlin/render.kts");
+			configurer.setRenderFunction("render");
+			return configurer;
+		}
+
+		@Bean
+		ResourceBundleMessageSource messageSource() {
+			ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
+			messageSource.setBasename("org/springframework/web/servlet/view/script/messages");
+			return messageSource;
+		}
+	}
+
+}