Add channel to the WebsocketConsumerServerHandler.CHANNELS before handshake

In attempt to fix a race condition in the tests

* Remove `log4j` deps as redundant: Spring Boot brings them anyway for logback compatibility
* Add `logback-test.xml` to the `spring-websocket-consumer.test` for test race condition failures

build.gradle

@@ -140,9 +140,6 @@ configure(javaProjects) { subproject ->
 		testImplementation 'org.awaitility:awaitility'
 		testImplementation 'org.testcontainers:junit-jupiter'
 
-		testRuntimeOnly 'org.apache.logging.log4j:log4j-core'
-		testRuntimeOnly 'org.apache.logging.log4j:log4j-jcl'
-
 		// NOTE: We explicitly specify checkstyle dep before javaformat checkstyle due to antlr class mismatch
 		checkstyle("com.puppycrawl.tools:checkstyle:${checkstyle.toolVersion}")
 		checkstyle("io.spring.javaformat:spring-javaformat-checkstyle:${javaFormatVersion}")

consumer/spring-websocket-consumer/src/main/java/org/springframework/cloud/fn/consumer/websocket/WebsocketConsumerServerHandler.java

@@ -120,8 +120,8 @@ public class WebsocketConsumerServerHandler extends SimpleChannelInboundHandler<
 			WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
 		}
 		else {
-			this.handshaker.handshake(ctx.channel(), req);
 			WebsocketConsumerServer.CHANNELS.add(ctx.channel());
+			this.handshaker.handshake(ctx.channel(), req);
 		}
 	}
 

consumer/spring-websocket-consumer/src/test/resources/logback-test.xml

@@ -0,0 +1,11 @@
+<configuration>
+	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+		<encoder>
+			<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+		</encoder>
+	</appender>
+	<root level="DEBUG">
+		<appender-ref ref="STDOUT" />
+	</root>
+	<logger name="org.springframework" level="DEBUG" />
+</configuration>