The test is flaky for HTTP 2:

https://ge.micronaut.io/scans/tests?search.buildOutcome=failure&search.rootProjectNames=micronaut-parent&search.tags=ci&search.timeZoneId=Europe%2FMadrid&tests.container=io.micronaut.http.server.tck.tests.forms.FormUrlEncodedBodyInRequestFilterTest&tests.test=bodyParsingInFilter()&tests.unstableOnly=false

I don’t think it is that the test is badly written. I think it is an underlying issue of the HTTP2 path:

https://ge.micronaut.io/s/vllxe5czbs5jw/tests/task/:test-suite-http2-server-tck-netty:test/details/io.micronaut.http.server.tck.tests.forms.FormUrlEncodedBodyInRequestFilterTest/bodyParsingInFilter()/1/output

```
00:57:25.989 [Test worker] INFO  i.m.c.DefaultApplicationContext$RuntimeConfiguredEnvironment - Established active environments: [test]
00:57:26.033 [Test worker] WARN  i.m.http.ssl.SslConfiguration - The configuration micronaut.ssl.port is deprecated. Use micronaut.server.ssl.port instead.
00:57:26.920 [Test worker] WARN  i.m.h.c.n.ssl.NettyClientSslBuilder - HTTP Client is configured to trust all certificates ('insecure-trust-all-certificates' is set to true). Trusting all certificates is not secure and should not be used in production.
00:57:26.997 [Test worker] INFO  i.m.c.DefaultApplicationContext$RuntimeConfiguredEnvironment - Established active environments: [test]
00:57:27.038 [Test worker] WARN  i.m.http.ssl.SslConfiguration - The configuration micronaut.ssl.port is deprecated. Use micronaut.server.ssl.port instead.
00:57:27.646 [Test worker] WARN  i.m.h.c.n.ssl.NettyClientSslBuilder - HTTP Client is configured to trust all certificates ('insecure-trust-all-certificates' is set to true). Trusting all certificates is not secure and should not be used in production.
00:57:27.754 [Test worker] INFO  i.m.c.DefaultApplicationContext$RuntimeConfiguredEnvironment - Established active environments: [test]
00:57:27.811 [Test worker] WARN  i.m.http.ssl.SslConfiguration - The configuration micronaut.ssl.port is deprecated. Use micronaut.server.ssl.port instead.
00:57:28.019 [Test worker] WARN  i.m.h.c.n.ssl.NettyClientSslBuilder - HTTP Client is configured to trust all certificates ('insecure-trust-all-certificates' is set to true). Trusting all certificates is not secure and should not be used in production.
00:57:28.079 [default-nioEventLoopGroup-140-4] WARN  i.m.h.s.netty.RoutingInBoundHandler - Failed to build error response
java.lang.AssertionError: null
	at io.micronaut.http.body.stream.BaseSharedBuffer.subscribe0(BaseSharedBuffer.java:205)
	at io.micronaut.http.netty.body.StreamingNettyByteBody$SharedBuffer.subscribe(StreamingNettyByteBody.java:259)
	at io.micronaut.http.netty.body.StreamingNettyByteBody.close(StreamingNettyByteBody.java:177)
	at io.micronaut.http.server.netty.NettyHttpRequest.release(NettyHttpRequest.java:388)
	at io.micronaut.http.server.netty.RoutingInBoundHandler.cleanupRequest(RoutingInBoundHandler.java:161)
	at io.micronaut.http.server.netty.RoutingInBoundHandler.responseWritten(RoutingInBoundHandler.java:178)
	at io.micronaut.http.server.netty.websocket.NettyServerWebSocketUpgradeHandler.responseWritten(NettyServerWebSocketUpgradeHandler.java:167)
	at io.micronaut.http.server.netty.handler.MultiplexedServerHandler$MultiplexedStream.finish(MultiplexedServerHandler.java:234)
	at io.micronaut.http.server.netty.handler.MultiplexedServerHandler$MultiplexedStream.writeFull(MultiplexedServerHandler.java:383)
	at io.micronaut.http.server.netty.handler.MultiplexedServerHandler$MultiplexedStream.write(MultiplexedServerHandler.java:260)
	at io.micronaut.http.server.netty.RoutingInBoundHandler.lambda$writeResponse$0(RoutingInBoundHandler.java:298)
	at io.micronaut.core.execution.ImperativeExecutionFlowImpl.onComplete(ImperativeExecutionFlowImpl.java:132)
	at io.micronaut.http.server.netty.RoutingInBoundHandler.writeResponse(RoutingInBoundHandler.java:274)
	at io.micronaut.http.server.netty.NettyRequestLifecycle.lambda$handleNormal$0(NettyRequestLifecycle.java:107)
	at io.micronaut.core.execution.ImperativeExecutionFlowImpl.onComplete(ImperativeExecutionFlowImpl.java:132)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl$OnComplete.apply(DelayedExecutionFlowImpl.java:379)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.work(DelayedExecutionFlowImpl.java:54)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.complete0(DelayedExecutionFlowImpl.java:72)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.complete(DelayedExecutionFlowImpl.java:78)
	at io.micronaut.http.body.stream.BaseSharedBuffer.subscribeFull0(BaseSharedBuffer.java:276)
	at io.micronaut.http.netty.body.StreamingNettyByteBody$SharedBuffer.lambda$subscribeFull$2(StreamingNettyByteBody.java:322)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:1583)
00:57:38.077 [default-nioEventLoopGroup-140-3] WARN  i.n.c.AbstractChannelHandlerContext - An exception 'java.lang.IllegalStateException: Already completed' [enable DEBUG level for full stacktrace] was thrown by a user handler's exceptionCaught() method while handling the following exception:
java.lang.IllegalStateException: Already completed
	at io.micronaut.core.execution.DelayedExecutionFlowImpl$Step.atomicSetOutput(DelayedExecutionFlowImpl.java:217)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.work(DelayedExecutionFlowImpl.java:55)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.complete0(DelayedExecutionFlowImpl.java:72)
	at io.micronaut.core.execution.DelayedExecutionFlowImpl.completeExceptionally(DelayedExecutionFlowImpl.java:83)
	at io.micronaut.http.client.netty.DefaultHttpClient$6.fail(DefaultHttpClient.java:1702)
	at io.micronaut.http.client.netty.Http1ResponseHandler$BeforeResponse.exceptionCaught(Http1ResponseHandler.java:147)
	at io.micronaut.http.client.netty.Http1ResponseHandler$ReaderState.channelInactive(Http1ResponseHandler.java:112)
	at io.micronaut.http.client.netty.Http1ResponseHandler.channelInactive(Http1ResponseHandler.java:83)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:303)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
	at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81)
	at io.netty.handler.codec.http.HttpContentDecoder.channelInactive(HttpContentDecoder.java:235)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:303)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1352)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:301)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
	at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:850)
	at io.netty.handler.codec.http2.AbstractHttp2StreamChannel$Http2ChannelUnsafe$2.run(AbstractHttp2StreamChannel.java:797)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:1583)
```

micronaut.ssl.port is deprecated