GH-1072 Add tests for ProxyMVC async start

spring-cloud-function-adapters/spring-cloud-function-serverless-web/src/main/java/org/springframework/cloud/function/serverless/web/ProxyMvc.java

@@ -69,7 +69,7 @@ public final class ProxyMvc {
 	/**
 	 * Name of the property to specify application context initialization timeout. Default is 20 sec.
 	 */
-	public static String INIT_TIMEOUT = "spring.cloud.function.serverless.web.init-timeout";
+	public static String INIT_TIMEOUT = "contextInitTimeout";
 
 	private static Log LOG = LogFactory.getLog(ProxyMvc.class);
 
@@ -91,6 +91,9 @@ public final class ProxyMvc {
 
 	private ProxyMvc() {
 		String timeoutValue = System.getenv(INIT_TIMEOUT);
+		if (!StringUtils.hasText(timeoutValue)) {
+			timeoutValue = System.getProperty(INIT_TIMEOUT);
+		}
 		this.initializatioinTimeout = StringUtils.hasText(timeoutValue) ? Long.valueOf(timeoutValue) : 20000;
 	}
 
@@ -164,6 +167,8 @@ public final class ProxyMvc {
 	public void service(HttpServletRequest request, HttpServletResponse response) throws Exception {
 		try {
 			contextStartupLatch.await(this.initializatioinTimeout, TimeUnit.MILLISECONDS);
+			Assert.state(this.dispatcher != null, "Failed to initialize Application within the specified time of " + this.initializatioinTimeout + " milliseconds. "
+					+ "If you need to increase it, please set " + INIT_TIMEOUT + " environment variable");
 		}
 		catch (InterruptedException e) {
 			Thread.currentThread().interrupt();

spring-cloud-function-adapters/spring-cloud-function-serverless-web/src/test/java/org/springframework/cloud/function/serverless/web/AsyncStartTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.serverless.web;
+
+import jakarta.servlet.http.HttpServletRequest;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.fail;
+
+/**
+ * @author Oleg Zhurakousky
+ */
+public class AsyncStartTests {
+
+	@Test
+	public void testAsync() throws Exception {
+		long start = System.currentTimeMillis();
+		ProxyMvc mvc = ProxyMvc.INSTANCE(SlowStartController.class);
+		assertThat(System.currentTimeMillis() - start).isLessThan(2000);
+		HttpServletRequest request = new ProxyHttpServletRequest(null, "GET", "/hello");
+		ProxyHttpServletResponse response = new ProxyHttpServletResponse();
+		mvc.service(request, response);
+		assertThat(System.currentTimeMillis() - start).isGreaterThan(2000);
+		assertThat(response.getContentAsString()).isEqualTo("hello");
+		assertThat(response.getStatus()).isEqualTo(200);
+	}
+
+	@Test
+	public void testAsyncWithEnvSet() throws Exception {
+		System.setProperty(ProxyMvc.INIT_TIMEOUT, "500");
+		long start = System.currentTimeMillis();
+		ProxyMvc mvc = ProxyMvc.INSTANCE(SlowStartController.class);
+		assertThat(System.currentTimeMillis() - start).isLessThan(2000);
+		HttpServletRequest request = new ProxyHttpServletRequest(null, "GET", "/hello");
+		ProxyHttpServletResponse response = new ProxyHttpServletResponse();
+		try {
+			mvc.service(request, response);
+			fail();
+		}
+		catch (Exception e) {
+			assertThat(e).isInstanceOf(IllegalStateException.class);
+			String message = e.getMessage();
+			assertThat(message).startsWith("Failed to initialize Application within the specified time");
+		}
+	}
+
+	@RestController
+	@EnableWebMvc
+	public static class SlowStartController {
+
+		public SlowStartController() throws Exception {
+			Thread.sleep(2000);
+		}
+
+		@RequestMapping(path = "/hello", method = RequestMethod.GET)
+		public String hello() {
+			return "hello";
+		}
+	}
+
+}