GH-3451: Use GreenMail for testing instead

Fixes https://github.com/spring-projects/spring-integration/issues/3451

The GreenMail provides a comprehensive support for e-mail scenarios
testing.

* Use GreenMail instead our own `TestMailServer` for better and broader
support
* Convert SmtpTests and Pop3Tests to GreenMail
* Document that Pop3MailReceiver does not support autoCloseFolder=false
* Pop3MailReceiver uses `folder.getMessageCount()` to determine if there
are new messages.
This count only gets updated when opening the folder.
* Use GreenMail for remaining mail tests
* convert MailTests and ImapMailReceiverTests to GreenMail
* remove duplicate mail dependencies
* route com.sun.mail logging to log4j (via jul and slf4j)

build.gradle

@@ -60,6 +60,7 @@ ext {
 	derbyVersion = '10.14.2.0'
 	ftpServerVersion = '1.1.1'
 	googleJsr305Version = '3.0.2'
+	greenmailVersion = '1.6.4'
 	groovyVersion = '3.0.8'
 	hamcrestVersion = '2.2'
 	hazelcastVersion = '4.2'
@@ -641,9 +642,9 @@ project('spring-integration-mail') {
 		api project(':spring-integration-core')
 		api 'org.springframework:spring-context-support'
 
-		providedImplementation "jakarta.mail:jakarta.mail-api:$mailVersion"
-		providedImplementation "com.sun.mail:imap:$mailVersion"
 		providedImplementation "com.sun.mail:jakarta.mail:$mailVersion"
+		testImplementation "com.icegreen:greenmail:$greenmailVersion"
+		testRuntimeOnly 'org.apache.logging.log4j:log4j-jul'
 	}
 }
 

spring-integration-mail/src/test/java/org/springframework/integration/mail/ImapMailReceiverTests.java

@@ -31,12 +31,18 @@ import static org.mockito.Mockito.verify;
 
 import java.io.IOException;
 import java.lang.reflect.Field;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.LogManager;
+import java.util.logging.LogRecord;
 
 import javax.mail.Flags;
 import javax.mail.Flags.Flag;
@@ -72,8 +78,6 @@ import org.springframework.integration.channel.QueueChannel;
 import org.springframework.integration.handler.AbstractReplyProducingMessageHandler;
 import org.springframework.integration.history.MessageHistory;
 import org.springframework.integration.mail.support.DefaultMailHeaderMapper;
-import org.springframework.integration.test.mail.TestMailServer;
-import org.springframework.integration.test.mail.TestMailServer.ImapServer;
 import org.springframework.integration.test.util.TestUtils;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.PollableChannel;
@@ -84,6 +88,11 @@ import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
 import org.springframework.util.MimeTypeUtils;
 
+import com.icegreen.greenmail.user.GreenMailUser;
+import com.icegreen.greenmail.util.GreenMail;
+import com.icegreen.greenmail.util.GreenMailUtil;
+import com.icegreen.greenmail.util.ServerSetup;
+import com.icegreen.greenmail.util.ServerSetupTest;
 import com.sun.mail.imap.IMAPFolder;
 
 /**
@@ -100,31 +109,43 @@ public class ImapMailReceiverTests {
 
 	private AtomicInteger failed;
 
-	private ImapServer imapIdleServer;
+	private GreenMail imapIdleServer;
+
+	private GreenMailUser user;
 
 	@Autowired
 	private ApplicationContext context;
 
+	static {
+		System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
+	}
+
+	private final ImapSearchLoggingHandler imapSearches = new ImapSearchLoggingHandler();
+
 	@BeforeEach
-	public void setup() throws InterruptedException {
+	public void setup() {
+		LogManager.getLogManager().getLogger("").setLevel(Level.ALL);
+		imapSearches.searches.clear();
+		imapSearches.stores.clear();
+		LogManager.getLogManager().getLogger("").addHandler(imapSearches);
 		failed = new AtomicInteger(0);
-		this.imapIdleServer = TestMailServer.imap(0);
-		int n = 0;
-		while (n++ < 100 && (!this.imapIdleServer.isListening())) {
-			Thread.sleep(100);
-		}
-		assertThat(n < 100).isTrue();
+		ServerSetup imap = ServerSetupTest.IMAP.dynamicPort();
+		imap.setServerStartupTimeout(10000);
+		imapIdleServer = new GreenMail(imap);
+		user = imapIdleServer.setUser("user", "pw");
+		imapIdleServer.start();
 	}
 
 	@AfterEach
 	public void tearDown() {
 		this.imapIdleServer.stop();
+		LogManager.getLogManager().getLogger("").removeHandler(imapSearches);
 	}
 
 	@Test
 	public void testIdleWithServerCustomSearch() throws Exception {
 		ImapMailReceiver receiver =
-				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getPort() + "/INBOX");
+				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getImap().getPort() + "/INBOX");
 		receiver.setSearchTermStrategy((supportedFlags, folder) -> {
 			try {
 				FromTerm fromTerm = new FromTerm(new InternetAddress("bar@baz"));
@@ -140,15 +161,15 @@ public class ImapMailReceiverTests {
 	@Test
 	public void testIdleWithServerDefaultSearch() throws Exception {
 		ImapMailReceiver receiver =
-				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getPort() + "/INBOX");
+				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getImap().getPort() + "/INBOX");
 		testIdleWithServerGuts(receiver, false);
-		assertThat(this.imapIdleServer.assertReceived("searchWithUserFlag")).isTrue();
+		assertThat(imapSearches.searches.get(0)).contains("testSIUserFlag");
 	}
 
 	@Test
 	public void testIdleWithMessageMapping() throws Exception {
 		ImapMailReceiver receiver =
-				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getPort() + "/INBOX");
+				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getImap().getPort() + "/INBOX");
 		receiver.setHeaderMapper(new DefaultMailHeaderMapper());
 		testIdleWithServerGuts(receiver, true);
 	}
@@ -156,16 +177,16 @@ public class ImapMailReceiverTests {
 	@Test
 	public void testIdleWithServerDefaultSearchSimple() throws Exception {
 		ImapMailReceiver receiver =
-				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getPort() + "/INBOX");
+				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getImap().getPort() + "/INBOX");
 		receiver.setSimpleContent(true);
 		testIdleWithServerGuts(receiver, false, true);
-		assertThat(this.imapIdleServer.assertReceived("searchWithUserFlag")).isTrue();
+		assertThat(imapSearches.searches.get(0)).contains("testSIUserFlag");
 	}
 
 	@Test
 	public void testIdleWithMessageMappingSimple() throws Exception {
 		ImapMailReceiver receiver =
-				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getPort() + "/INBOX");
+				new ImapMailReceiver("imap://user:pw@localhost:" + this.imapIdleServer.getImap().getPort() + "/INBOX");
 		receiver.setSimpleContent(true);
 		receiver.setHeaderMapper(new DefaultMailHeaderMapper());
 		testIdleWithServerGuts(receiver, true, true);
@@ -176,10 +197,6 @@ public class ImapMailReceiverTests {
 	}
 
 	public void testIdleWithServerGuts(ImapMailReceiver receiver, boolean mapped, boolean simple) throws Exception {
-		Properties mailProps = new Properties();
-		mailProps.put("mail.debug", "true");
-		mailProps.put("mail.imap.connectionpool.debug", "true");
-		receiver.setJavaMailProperties(mailProps);
 		receiver.setMaxFetchSize(1);
 		receiver.setShouldDeleteMessages(false);
 		receiver.setShouldMarkMessagesAsRead(true);
@@ -193,6 +210,14 @@ public class ImapMailReceiverTests {
 		adapter.setTaskScheduler(taskScheduler);
 		adapter.setReconnectDelay(1);
 		adapter.start();
+		MimeMessage message =
+				GreenMailUtil.createTextEmail("Foo <foo@bar>", "Bar <bar@baz>", "Test Email", "foo\r\n",
+						imapIdleServer.getImap().getServerSetup());
+		message.setRecipients(Message.RecipientType.CC, "a@b, c@d");
+		message.setRecipients(Message.RecipientType.BCC, "e@f, g@h");
+		user.deliver(message);
+		user.deliver(GreenMailUtil.createTextEmail("to", "Bar <bar@baz>", "subject", "body",
+				imapIdleServer.getImap().getServerSetup()));
 		if (!mapped) {
 			@SuppressWarnings("unchecked")
 			org.springframework.messaging.Message<MimeMessage> received =
@@ -202,11 +227,11 @@ public class ImapMailReceiverTests {
 			assertThat(received.getPayload().getLineCount() > -1).isTrue();
 			if (simple) {
 				assertThat(received.getPayload().getContent())
-						.isEqualTo(TestMailServer.MailServer.MailHandler.BODY + "\r\n");
+						.isEqualTo("foo\r\n");
 			}
 			else {
 				assertThat(received.getPayload().getContent())
-						.isEqualTo(TestMailServer.MailServer.MailHandler.MESSAGE + "\r\n");
+						.isEqualTo("foo");
 			}
 		}
 		else {
@@ -214,7 +239,7 @@ public class ImapMailReceiverTests {
 			assertThat(received).isNotNull();
 			MessageHeaders headers = received.getHeaders();
 			assertThat(headers.get(MailHeaders.RAW_HEADERS)).isNotNull();
-			assertThat(headers.get(MailHeaders.CONTENT_TYPE)).isEqualTo("TEXT/PLAIN; charset=ISO-8859-1");
+			assertThat(headers.get(MailHeaders.CONTENT_TYPE)).isEqualTo("TEXT/PLAIN; charset=us-ascii");
 			assertThat(headers.get(MessageHeaders.CONTENT_TYPE)).isEqualTo(MimeTypeUtils.TEXT_PLAIN_VALUE);
 			assertThat(headers.get(MailHeaders.FROM)).isEqualTo("Bar <bar@baz>");
 			String[] toHeader = headers.get(MailHeaders.TO, String[].class);
@@ -224,10 +249,10 @@ public class ImapMailReceiverTests {
 			assertThat(Arrays.toString(headers.get(MailHeaders.BCC, String[].class))).isEqualTo("[e@f, g@h]");
 			assertThat(headers.get(MailHeaders.SUBJECT)).isEqualTo("Test Email");
 			if (simple) {
-				assertThat(received.getPayload()).isEqualTo(TestMailServer.MailServer.MailHandler.BODY + "\r\n");
+				assertThat(received.getPayload()).isEqualTo("foo\r\n");
 			}
 			else {
-				assertThat(received.getPayload()).isEqualTo(TestMailServer.MailServer.MailHandler.MESSAGE + "\r\n");
+				assertThat(received.getPayload()).isEqualTo("foo");
 			}
 		}
 		assertThat(channel.receive(20000)).isNotNull(); // new message after idle
@@ -235,11 +260,13 @@ public class ImapMailReceiverTests {
 
 		adapter.stop();
 		taskScheduler.shutdown();
-		assertThat(this.imapIdleServer.assertReceived("storeUserFlag")).isTrue();
+		assertThat(imapSearches.stores.get(0)).contains("testSIUserFlag");
 	}
 
 	@Test
 	public void receiveAndMarkAsReadDontDelete() throws Exception {
+		user.deliver(GreenMailUtil.createTextEmail("user", "sender", "subject", "body",
+				imapIdleServer.getImap().getServerSetup()));
 		AbstractMailReceiver receiver = new ImapMailReceiver();
 		Message msg1 = mock(MimeMessage.class);
 		Message msg2 = mock(MimeMessage.class);
@@ -898,4 +925,40 @@ public class ImapMailReceiverTests {
 		mailReceiver.setBeanFactory(bf);
 	}
 
+
+	private static class ImapSearchLoggingHandler extends Handler {
+
+		private final List<String> searches = new ArrayList<>();
+
+		private final List<String> stores = new ArrayList<>();
+
+		private static final String SEARCH = " SEARCH ";
+
+		private static final String STORE = " STORE ";
+
+		@Override
+		public void publish(LogRecord record) {
+			if ("com.sun.mail.imap.protocol".equals(record.getLoggerName())) {
+				String message = record.getMessage();
+				if (!message.startsWith("*")) {
+					if (message.contains(SEARCH) && !message.contains(" OK ")) {
+						searches.add(message.substring(message.indexOf(SEARCH) + SEARCH.length()));
+					}
+					else if (message.contains(STORE) && !message.contains(" OK ")) {
+						stores.add(message.substring(message.indexOf(STORE) + STORE.length()));
+					}
+				}
+			}
+		}
+
+		@Override
+		public void flush() {
+		}
+
+		@Override
+		public void close() throws SecurityException {
+		}
+
+	}
+
 }

spring-integration-mail/src/test/java/org/springframework/integration/mail/config/Pop3Tests.java

@@ -20,6 +20,10 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Arrays;
 
+import javax.mail.Message.RecipientType;
+import javax.mail.MessagingException;
+import javax.mail.internet.MimeMessage;
+
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -28,29 +32,36 @@ import org.springframework.integration.mail.MailHeaders;
 import org.springframework.integration.mail.MailReceivingMessageSource;
 import org.springframework.integration.mail.Pop3MailReceiver;
 import org.springframework.integration.mail.support.DefaultMailHeaderMapper;
-import org.springframework.integration.test.mail.TestMailServer;
-import org.springframework.integration.test.mail.TestMailServer.Pop3Server;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 
+import com.icegreen.greenmail.user.GreenMailUser;
+import com.icegreen.greenmail.util.GreenMail;
+import com.icegreen.greenmail.util.GreenMailUtil;
+import com.icegreen.greenmail.util.ServerSetup;
+import com.icegreen.greenmail.util.ServerSetupTest;
+
 /**
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Alexander Pinske
  *
  * @since 5.0
  *
  */
 public class Pop3Tests {
 
-	private static final Pop3Server pop3Server = TestMailServer.pop3(0);
+	private static GreenMail pop3Server;
+
+	private static GreenMailUser user;
 
 	@BeforeAll
-	public static void setup() throws InterruptedException {
-		int n = 0;
-		while (n++ < 100 && (!pop3Server.isListening())) {
-			Thread.sleep(100);
-		}
-		assertThat(n < 100).isTrue();
+	public static void setup() {
+		ServerSetup pop3 = ServerSetupTest.POP3.dynamicPort();
+		pop3.setServerStartupTimeout(10000);
+		pop3Server = new GreenMail(pop3);
+		user = pop3Server.setUser("user", "pw");
+		pop3Server.start();
 	}
 
 	@AfterAll
@@ -59,8 +70,15 @@ public class Pop3Tests {
 	}
 
 	@Test
-	public void testPop3() {
-		Pop3MailReceiver receiver = new Pop3MailReceiver("localhost", pop3Server.getPort(), "user", "pw");
+	public void testPop3() throws MessagingException {
+		MimeMessage mimeMessage =
+				GreenMailUtil.createTextEmail("Foo <foo@bar>", "Bar <bar@baz>, Bar2 <bar2@baz>", "Test Email",
+						"foo\r\n", pop3Server.getPop3().getServerSetup());
+		mimeMessage.setRecipients(RecipientType.CC, "a@b, c@d");
+		mimeMessage.setRecipients(RecipientType.BCC, "e@f, g@h");
+		user.deliver(mimeMessage);
+
+		Pop3MailReceiver receiver = new Pop3MailReceiver("localhost", pop3Server.getPop3().getPort(), "user", "pw");
 		receiver.setHeaderMapper(new DefaultMailHeaderMapper());
 		MailReceivingMessageSource source = new MailReceivingMessageSource(receiver);
 		Message<?> message = source.receive();
@@ -71,7 +89,7 @@ public class Pop3Tests {
 		assertThat(Arrays.toString(headers.get(MailHeaders.BCC, String[].class))).isEqualTo("[e@f, g@h]");
 		assertThat(headers.get(MailHeaders.FROM)).isEqualTo("Bar <bar@baz>,Bar2 <bar2@baz>");
 		assertThat(headers.get(MailHeaders.SUBJECT)).isEqualTo("Test Email");
-		assertThat(message.getPayload()).isEqualTo("foo\r\n\r\n");
+		assertThat(message.getPayload()).isEqualTo("foo\r\n");
 	}
 
 }

spring-integration-mail/src/test/java/org/springframework/integration/mail/config/SmtpTests.java

@@ -18,6 +18,10 @@ package org.springframework.integration.mail.config;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import javax.mail.Message.RecipientType;
+import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeMessage;
+
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -25,28 +29,31 @@ import org.junit.jupiter.api.Test;
 import org.springframework.integration.mail.MailHeaders;
 import org.springframework.integration.mail.MailSendingMessageHandler;
 import org.springframework.integration.support.MessageBuilder;
-import org.springframework.integration.test.mail.TestMailServer;
-import org.springframework.integration.test.mail.TestMailServer.SmtpServer;
 import org.springframework.mail.javamail.JavaMailSenderImpl;
 
+import com.icegreen.greenmail.util.GreenMail;
+import com.icegreen.greenmail.util.ServerSetup;
+import com.icegreen.greenmail.util.ServerSetupTest;
+
 /**
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Alexander Pinske
  *
  * @since 5.0
  *
  */
 public class SmtpTests {
 
-	private static final SmtpServer smtpServer = TestMailServer.smtp(0);
+	private static GreenMail smtpServer;
 
 	@BeforeAll
-	public static void setup() throws InterruptedException {
-		int n = 0;
-		while (n++ < 100 && (!smtpServer.isListening())) {
-			Thread.sleep(100);
-		}
-		assertThat(n < 100).isTrue();
+	public static void setup() {
+		ServerSetup smtp = ServerSetupTest.SMTP.dynamicPort();
+		smtp.setServerStartupTimeout(10000);
+		smtpServer = new GreenMail(smtp);
+		smtpServer.setUser("user", "pw");
+		smtpServer.start();
 	}
 
 	@AfterAll
@@ -58,7 +65,7 @@ public class SmtpTests {
 	public void testSmtp() throws Exception {
 		JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
 		mailSender.setHost("localhost");
-		mailSender.setPort(smtpServer.getPort());
+		mailSender.setPort(smtpServer.getSmtp().getPort());
 		mailSender.setUsername("user");
 		mailSender.setPassword("pw");
 		MailSendingMessageHandler handler = new MailSendingMessageHandler(mailSender);
@@ -69,19 +76,14 @@ public class SmtpTests {
 				.setHeader(MailHeaders.SUBJECT, "foo")
 				.build());
 
-		int n = 0;
-		while (n++ < 100 && smtpServer.getMessages().size() == 0) {
-			Thread.sleep(100);
-		}
+		assertThat(smtpServer.waitForIncomingEmail(10000, 1)).isTrue();
 
-		assertThat(smtpServer.getMessages().size() > 0).isTrue();
-		String message = smtpServer.getMessages().get(0);
-		assertThat(message)
-				.endsWith("foo\n")
-				.contains("foo@bar")
-				.contains("bar@baz")
-				.contains("user:user")
-				.contains("password:pw");
+		assertThat(smtpServer.getReceivedMessages().length > 0).isTrue();
+		MimeMessage message = smtpServer.getReceivedMessages()[0];
+		assertThat(message.getFrom()).containsOnly(new InternetAddress("foo@bar"));
+		assertThat(message.getRecipients(RecipientType.TO)).containsOnly(new InternetAddress("bar@baz"));
+		assertThat(message.getSubject()).isEqualTo("foo");
+		assertThat(message.getContent()).asString().isEqualTo("foo\r\n");
 	}
 
 }

spring-integration-mail/src/test/java/org/springframework/integration/mail/dsl/MailTests.java

@@ -19,7 +19,6 @@ package org.springframework.integration.mail.dsl;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.Closeable;
-import java.io.IOException;
 import java.util.Properties;
 
 import javax.mail.Flags;
@@ -33,12 +32,12 @@ import javax.mail.search.FlagTerm;
 import javax.mail.search.FromTerm;
 import javax.mail.search.SearchTerm;
 
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.context.SmartLifecycle;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.integration.IntegrationMessageHeaderAccessor;
@@ -51,10 +50,6 @@ import org.springframework.integration.mail.MailHeaders;
 import org.springframework.integration.mail.support.DefaultMailHeaderMapper;
 import org.springframework.integration.mapping.HeaderMapper;
 import org.springframework.integration.support.MessageBuilder;
-import org.springframework.integration.test.mail.TestMailServer;
-import org.springframework.integration.test.mail.TestMailServer.ImapServer;
-import org.springframework.integration.test.mail.TestMailServer.Pop3Server;
-import org.springframework.integration.test.mail.TestMailServer.SmtpServer;
 import org.springframework.integration.test.util.TestUtils;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
@@ -64,31 +59,41 @@ import org.springframework.messaging.PollableChannel;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
 
+import com.icegreen.greenmail.util.GreenMail;
+import com.icegreen.greenmail.util.GreenMailUtil;
+import com.icegreen.greenmail.util.ServerSetup;
+import com.icegreen.greenmail.util.ServerSetupTest;
+
 /**
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Alexander Pinske
  */
 @SpringJUnitConfig
 @DirtiesContext
 public class MailTests {
 
-	private static final SmtpServer smtpServer = TestMailServer.smtp(0);
-
-	private static final Pop3Server pop3Server = TestMailServer.pop3(0);
-
-	private static final ImapServer imapServer = TestMailServer.imap(0);
-
-	private static final ImapServer imapIdleServer = TestMailServer.imap(0);
-
+	private static GreenMail mailServer;
 
 	@BeforeAll
-	public static void setup() throws InterruptedException {
-		int n = 0;
-		while (n++ < 100 && (!smtpServer.isListening() || !pop3Server.isListening()
-				|| !imapServer.isListening()) || !imapIdleServer.isListening()) {
-			Thread.sleep(100);
-		}
-		assertThat(n < 100).isTrue();
+	public static void setup() {
+		ServerSetup smtp = ServerSetupTest.SMTP.dynamicPort();
+		smtp.setServerStartupTimeout(10000);
+		ServerSetup imap = ServerSetupTest.IMAP.dynamicPort();
+		imap.setServerStartupTimeout(10000);
+		ServerSetup pop3 = ServerSetupTest.POP3.dynamicPort();
+		pop3.setServerStartupTimeout(10000);
+		mailServer = new GreenMail(new ServerSetup[]{ smtp, pop3, imap });
+		mailServer.setUser("bar@baz", "smtpuser", "pw");
+		mailServer.setUser("popuser", "pw");
+		mailServer.setUser("imapuser", "pw");
+		mailServer.setUser("imapidleuser", "pw");
+		mailServer.start();
+	}
+
+	@AfterAll
+	static void tearDown() {
+		mailServer.stop();
 	}
 
 	@Autowired
@@ -120,56 +125,72 @@ public class MailTests {
 
 		this.sendMailChannel.send(MessageBuilder.withPayload("foo").build());
 
-		int n = 0;
-		while (n++ < 100 && smtpServer.getMessages().size() == 0) {
-			Thread.sleep(100);
-		}
+		mailServer.waitForIncomingEmail(10000, 1);
 
-		assertThat(smtpServer.getMessages().size() > 0).isTrue();
-		String message = smtpServer.getMessages().get(0);
-		assertThat(message).endsWith("foo\n");
-		assertThat(message).contains("foo@bar");
-		assertThat(message).contains("bar@baz");
-		assertThat(message).contains("user:user");
-		assertThat(message).contains("password:pw");
+		assertThat(mailServer.getReceivedMessagesForDomain("baz").length > 0).isTrue();
+		MimeMessage message = mailServer.getReceivedMessagesForDomain("baz")[0];
+		assertThat(message.getFrom()).containsOnly(new InternetAddress("foo@bar"));
+		assertThat(message.getRecipients(RecipientType.TO)).containsOnly(new InternetAddress("bar@baz"));
+		assertThat(message.getSubject()).isEqualTo("foo");
+		assertThat(message.getContent()).asString().isEqualTo("foo\r\n");
 
 	}
 
 	@Test
-	public void testPop3() throws IOException {
+	public void testPop3() throws Exception {
+		MimeMessage mimeMessage =
+				GreenMailUtil.createTextEmail("Foo <foo@bar>", "Bar <bar@baz>, Bar2 <bar2@baz>", "Test Email",
+						"foo\r\n", mailServer.getPop3().getServerSetup());
+		mimeMessage.setRecipients(RecipientType.CC, "a@b, c@d");
+		mimeMessage.setRecipients(RecipientType.BCC, "e@f, g@h");
+		mailServer.getUserManager().getUser("popuser").deliver(mimeMessage);
+
 		Message<?> message = this.pop3Channel.receive(10000);
 		assertThat(message).isNotNull();
 		MessageHeaders headers = message.getHeaders();
 		assertThat(headers.get(MailHeaders.TO, String[].class)).containsExactly("Foo <foo@bar>");
 		assertThat(headers.get(MailHeaders.FROM)).isEqualTo("Bar <bar@baz>,Bar2 <bar2@baz>");
 		assertThat(headers.get(MailHeaders.SUBJECT)).isEqualTo("Test Email");
-		assertThat(message.getPayload()).isEqualTo("foo\r\n\r\n");
-		assertThat(message.getHeaders().containsKey(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE)).isTrue();
-		message.getHeaders().get(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE, Closeable.class).close();
+		assertThat(message.getPayload()).isEqualTo("foo\r\n");
+		assertThat(message.getHeaders().containsKey(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE)).isFalse();
 	}
 
 	@Test
 	public void testImap() throws Exception {
+		MimeMessage mimeMessage =
+				GreenMailUtil.createTextEmail("Foo <foo@bar>", "Bar <bar@baz>", "Test Email", "foo\r\n",
+						mailServer.getImap().getServerSetup());
+		mimeMessage.setRecipients(RecipientType.CC, "a@b, c@d");
+		mimeMessage.setRecipients(RecipientType.BCC, "e@f, g@h");
+		mailServer.getUserManager().getUser("imapuser").deliver(mimeMessage);
+
 		Message<?> message = this.imapChannel.receive(10000);
 		assertThat(message).isNotNull();
 		MimeMessage mm = (MimeMessage) message.getPayload();
 		assertThat(mm.getRecipients(RecipientType.TO)[0].toString()).isEqualTo("Foo <foo@bar>");
 		assertThat(mm.getFrom()[0].toString()).isEqualTo("Bar <bar@baz>");
 		assertThat(mm.getSubject()).isEqualTo("Test Email");
-		assertThat(mm.getContent()).isEqualTo(TestMailServer.MailServer.MailHandler.BODY + "\r\n");
+		assertThat(mm.getContent()).isEqualTo("foo\r\n");
 		assertThat(message.getHeaders().containsKey(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE)).isTrue();
 		message.getHeaders().get(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE, Closeable.class).close();
 	}
 
 	@Test
-	public void testImapIdle() {
+	public void testImapIdle() throws Exception {
+		MimeMessage mimeMessage =
+				GreenMailUtil.createTextEmail("Foo <foo@bar>", "Bar <bar@baz>", "Test Email", "foo\r\n",
+						mailServer.getImap().getServerSetup());
+		mimeMessage.setRecipients(RecipientType.CC, "a@b, c@d");
+		mimeMessage.setRecipients(RecipientType.BCC, "e@f, g@h");
+		mailServer.getUserManager().getUser("imapidleuser").deliver(mimeMessage);
+
 		Message<?> message = this.imapIdleChannel.receive(10000);
 		assertThat(message).isNotNull();
 		MessageHeaders headers = message.getHeaders();
 		assertThat(headers.get(MailHeaders.TO, String[].class)).containsExactly("Foo <foo@bar>");
 		assertThat(headers.get(MailHeaders.FROM)).isEqualTo("Bar <bar@baz>");
 		assertThat(headers.get(MailHeaders.SUBJECT)).isEqualTo("Test Email");
-		assertThat(message.getPayload()).isEqualTo(TestMailServer.MailServer.MailHandler.BODY + "\r\n");
+		assertThat(message.getPayload()).isEqualTo("foo\r\n");
 		assertThat(message.getHeaders().containsKey(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE)).isTrue();
 		this.imapIdleAdapter.stop();
 		assertThat(TestUtils.getPropertyValue(this.imapIdleAdapter, "shouldReconnectAutomatically", Boolean.class))
@@ -180,35 +201,6 @@ public class MailTests {
 	@EnableIntegration
 	public static class ContextConfiguration {
 
-		@Bean
-		public SmartLifecycle serverStopper() {
-			return new SmartLifecycle() {
-
-				@Override
-				public int getPhase() {
-					return Integer.MAX_VALUE;
-				}
-
-				@Override
-				public void stop() {
-					smtpServer.stop();
-					pop3Server.stop();
-					imapServer.stop();
-					imapIdleServer.stop();
-				}
-
-				@Override
-				public void start() {
-				}
-
-				@Override
-				public boolean isRunning() {
-					return true;
-				}
-
-			};
-		}
-
 		@Bean
 		public IntegrationFlow sendMailFlow() {
 			return IntegrationFlows.from("sendMailChannel")
@@ -217,8 +209,8 @@ public class MailTests {
 							.from("foo@bar")
 							.toFunction(m -> new String[]{ "bar@baz" }))
 					.handle(Mail.outboundAdapter("localhost")
-									.port(smtpServer.getPort())
-									.credentials("user", "pw")
+									.port(mailServer.getSmtp().getPort())
+									.credentials("smtpuser", "pw")
 									.protocol("smtp")
 									.javaMailProperties(p -> p.put("mail.debug", "false")),
 							e -> e.id("sendMailEndpoint"))
@@ -228,9 +220,9 @@ public class MailTests {
 		@Bean
 		public IntegrationFlow pop3MailFlow() {
 			return IntegrationFlows
-					.from(Mail.pop3InboundAdapter("localhost", pop3Server.getPort(), "user", "pw")
+					.from(Mail.pop3InboundAdapter("localhost", mailServer.getPop3().getPort(), "popuser", "pw")
 									.javaMailProperties(p -> p.put("mail.debug", "false"))
-									.autoCloseFolder(false)
+									.autoCloseFolder(true)
 									.headerMapper(mailHeaderMapper()),
 							e -> e.autoStartup(true).poller(p -> p.fixedDelay(1000)))
 					.enrichHeaders(s -> s.headerExpressions(c -> c.put(MailHeaders.SUBJECT, "payload.subject")
@@ -242,7 +234,7 @@ public class MailTests {
 		@Bean
 		public IntegrationFlow imapMailFlow() {
 			return IntegrationFlows
-					.from(Mail.imapInboundAdapter("imap://user:pw@localhost:" + imapServer.getPort() + "/INBOX")
+					.from(Mail.imapInboundAdapter("imap://imapuser:pw@localhost:" + mailServer.getImap().getPort() + "/INBOX")
 									.searchTermStrategy(this::fromAndNotSeenTerm)
 									.userFlag("testSIUserFlag")
 									.autoCloseFolder(false)
@@ -257,7 +249,7 @@ public class MailTests {
 		@Bean
 		public IntegrationFlow imapIdleFlow() {
 			return IntegrationFlows
-					.from(Mail.imapIdleAdapter("imap://user:pw@localhost:" + imapIdleServer.getPort() + "/INBOX")
+					.from(Mail.imapIdleAdapter("imap://imapidleuser:pw@localhost:" + mailServer.getImap().getPort() + "/INBOX")
 							.autoStartup(true)
 							.searchTermStrategy(this::fromAndNotSeenTerm)
 							.userFlag("testSIUserFlag")

spring-integration-mail/src/test/resources/log4j2-test.xml

@@ -8,6 +8,8 @@
 	<Loggers>
 		<Logger name="org.springframework.integration" level="warn"/>
 		<Logger name="org.springframework.integration.mail" level="warn"/>
+		<Logger name="com.icegreen.greenmail" level="warn"/>
+		<Logger name="com.sun.mail" level="warn"/>
 		<Root level="warn">
 			<AppenderRef ref="STDOUT" />
 		</Root>

spring-integration-test-support/src/main/java/org/springframework/integration/test/mail/TestMailServer.java

@@ -48,7 +48,10 @@ import org.springframework.util.Base64Utils;
  *
  * @since 5.0
  *
+ * @deprecated since 5.5 in favor of GreenMail library for mail testing.
+ *
  */
+@Deprecated
 public final class TestMailServer {
 
 	public static SmtpServer smtp(int port) {

src/reference/asciidoc/mail.adoc

@@ -119,6 +119,7 @@ It now allows body-only rendering when a header mapper is provided.
 
 Starting with version 5.2, the `autoCloseFolder` option is provided on the mail receiver.
 Setting it to `false` doesn't close the folder automatically after a fetch, but instead an `IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE` header (see <<./message.adoc#message-header-accessor,`MessageHeaderAccessor` API>> for more information) is populated into every message to producer from the channel adapter.
+This does not work with `Pop3MailReceiver` as it relies on opening and closing the folder to get new messages.
 It is the target application's responsibility to call the `close()` on this header whenever it is necessary in the downstream flow:
 
 ====

src/reference/asciidoc/testing.adoc

@@ -33,6 +33,7 @@ Examples of such tools include the following:
 * Gemfire and Hazelcast can be run as real-data grid nodes in the tests.
 * The Curator Framework provides a `TestingServer` for Zookeeper interaction.
 * Apache Kafka provides admin tools to embed a Kafka Broker in the tests.
+* The GreenMail is an open source, intuitive and easy-to-use test suite of email servers for testing purposes.
 
 Most of these tools and libraries are used in Spring Integration tests.
 Also, from the GitHub https://github.com/spring-projects/spring-integration[repository] (in the `test` directory of each module), you can discover ideas for how to build your own tests for integration solutions.
@@ -97,7 +98,7 @@ private UdpSyslogReceivingChannelAdapter adapter;
 
 @Autowired
 private PollableChannel sysLogs;
-...
+
 @Test
 public void testSimplestUdp() throws Exception {
     int port = TestUtils.getPropertyValue(adapter1, "udpAdapter.port", Integer.class);
@@ -145,7 +146,7 @@ PollerMetadata poller;
 
 @Autowired
 OnlyOnceTrigger testTrigger;
-...
+
 @Test
 @DirtiesContext
 public void testWithEntityClass() throws Exception {
@@ -363,7 +364,7 @@ assertEquals("FOO", receive.getPayload());
 Unlike the Mockito `MessageSource` mock object, the `MockMessageHandler` is a regular `AbstractMessageProducingHandler` extension with a chain API to stub handling for incoming messages.
 The `MockMessageHandler` provides `handleNext(Consumer<Message<?>>)` to specify a one-way stub for the next request message.
 It is used to mock message handlers that do not produce replies.
-`handleNextAndReply(Function<Message<?>, ?>)` is provided for performing the same stub logic for the next request message and producing a reply for it.
+The `handleNextAndReply(Function<Message<?>, ?>)` is provided for performing the same stub logic for the next request message and producing a reply for it.
 They can be chained to simulate any arbitrary request-reply scenarios for all expected request messages variants.
 These consumers and functions are applied to the incoming messages, one at a time from the stack, until the last, which is then used for all remaining messages.
 The behavior is similar to the Mockito `Answer` or `doReturn()` API.