Error When Starting Twice

Issue gh-1025

test-support/src/main/java/org/springframework/ldap/test/unboundid/EmbeddedLdapServer.java

@@ -23,6 +23,8 @@
 import com.unboundid.ldap.sdk.Entry;
 import com.unboundid.ldap.sdk.LDAPException;
 
+import org.springframework.util.Assert;
+
 /**
  * Helper class for embedded Unboundid ldap server.
  *
@@ -33,7 +35,13 @@ public final class EmbeddedLdapServer implements AutoCloseable {
 
 	private final InMemoryDirectoryServer directoryServer;
 
-	private EmbeddedLdapServer(InMemoryDirectoryServer directoryServer) {
+	/**
+	 * Construct an {@link EmbeddedLdapServer} using the provided
+	 * {@link InMemoryDirectoryServer}.
+	 *
+	 * @since 3.3
+	 */
+	public EmbeddedLdapServer(InMemoryDirectoryServer directoryServer) {
 		this.directoryServer = directoryServer;
 	}
 
@@ -66,6 +74,7 @@ public static EmbeddedLdapServer newEmbeddedServer(String defaultPartitionName,
 	 * @since 3.3
 	 */
 	public void start() {
+		Assert.isTrue(this.directoryServer.getListenPort() == -1, "The server has already been started.");
 		try {
 			this.directoryServer.startListening();
 		}

test-support/src/test/java/org/springframework/ldap/test/unboundid/EmbeddedLdapServerTests.java

@@ -20,9 +20,13 @@
 import java.net.ServerSocket;
 import java.net.Socket;
 
+import com.unboundid.ldap.listener.InMemoryDirectoryServer;
+import com.unboundid.ldap.listener.InMemoryDirectoryServerConfig;
+import com.unboundid.ldap.listener.InMemoryListenerConfig;
 import org.junit.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 public class EmbeddedLdapServerTests {
 
@@ -61,6 +65,38 @@ public void shouldStartAndCloseServerViaLdapTestUtils() throws Exception {
 		assertThat(isPortOpen(port)).isFalse();
 	}
 
+	@Test
+	public void startWhenNewEmbeddedServerThenException() throws Exception {
+		int port = getFreePort();
+		EmbeddedLdapServer server = EmbeddedLdapServer.newEmbeddedServer("jayway", "dc=jayway,dc=se", port);
+		assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(server::start);
+	}
+
+	@Test
+	public void startWhenUnstartedThenWorks() throws Exception {
+		int port = getFreePort();
+		InMemoryDirectoryServerConfig config = new InMemoryDirectoryServerConfig("dc=jayway,dc=se");
+		config.setListenerConfigs(InMemoryListenerConfig.createLDAPConfig("LDAP", port));
+		InMemoryDirectoryServer ds = new InMemoryDirectoryServer(config);
+		try (EmbeddedLdapServer server = new EmbeddedLdapServer(ds)) {
+			server.start();
+			assertThat(isPortOpen(port)).isTrue();
+		}
+	}
+
+	@Test
+	public void startWhenAlreadyStartedThenFails() throws Exception {
+		int port = getFreePort();
+		InMemoryDirectoryServerConfig config = new InMemoryDirectoryServerConfig("dc=jayway,dc=se");
+		config.setListenerConfigs(InMemoryListenerConfig.createLDAPConfig("LDAP", port));
+		InMemoryDirectoryServer ds = new InMemoryDirectoryServer(config);
+		try (EmbeddedLdapServer server = new EmbeddedLdapServer(ds)) {
+			server.start();
+			assertThat(isPortOpen(port)).isTrue();
+			assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(server::start);
+		}
+	}
+
 	static boolean isPortOpen(int port) {
 		try (Socket ignored = new Socket("localhost", port)) {
 			return true;