Fixes the DelayOnHeadDelegate test utility (#374)

Currently the DelayOnHeadDelegate test utility depends on correct timings. Right now, if a request is slower than 50ms in `testErrorAfterCloseWhileBackpressureExerted` the test will fail, since the backpressure promise is failed, before a head was received. This pr fixes this, by giving the user a callback, when the head was received.

Author: fabianfett

Tests/AsyncHTTPClientTests/HTTPClientTestUtils.swift

@@ -104,36 +104,44 @@ class CountingDelegate: HTTPClientResponseDelegate{
 classDelayOnHeadDelegate:HTTPClientResponseDelegate{
 typealiasResponse=ByteBuffer
 
-letpromise:EventLoopPromise<Void>
+leteventLoop:EventLoop
+letdidReceiveHead:(HTTPResponseHead,EventLoopPromise<Void>)->Void
 
 privatevardata:ByteBuffer
 
 privatevarmayReceiveData=false
 
 privatevarexpectError=false
 
-init(promise:EventLoopPromise<Void>){
-self.promise = promise
+init(eventLoop:EventLoop, didReceiveHead:@escaping(HTTPResponseHead,EventLoopPromise<Void>)->Void){
+self.eventLoop = eventLoop
+self.didReceiveHead = didReceiveHead
 self.data =ByteBuffer()
-
-self.promise.futureResult.whenSuccess{
-self.mayReceiveData =true
-}
-self.promise.futureResult.whenFailure{(_:Error)in
-self.expectError =true
-}
 }
 
 func didReceiveHead(task:HTTPClient.Task<Response>, _ head:HTTPResponseHead)->EventLoopFuture<Void>{
+XCTAssertFalse(self.mayReceiveData)
 XCTAssertFalse(self.expectError)
-returnself.promise.futureResult.hop(to: task.eventLoop)
+
+letpromise=self.eventLoop.makePromise(of:Void.self)
+ promise.futureResult.whenComplete{
+switch $0 {
+case.success:
+self.mayReceiveData =true
+case.failure:
+self.expectError =true
+}
+}
+
+self.didReceiveHead(head, promise)
+return promise.futureResult
 }
 
 func didReceiveBodyPart(task:HTTPClient.Task<Response>, _ buffer:ByteBuffer)->EventLoopFuture<Void>{
 XCTAssertTrue(self.mayReceiveData)
 XCTAssertFalse(self.expectError)
 self.data.writeImmutableBuffer(buffer)
-returnself.promise.futureResult.hop(to: task.eventLoop)
+returnself.eventLoop.makeSucceededFuture(())
 }
 
 func didFinishRequest(task:HTTPClient.Task<Response>)throws->Response{

Tests/AsyncHTTPClientTests/HTTPClientTests.swift

@@ -2895,16 +2895,14 @@ class HTTPClientTests: XCTestCase{
 
 func testCloseWhileBackpressureIsExertedIsFine()throws{
 letrequest=tryRequest(url:self.defaultHTTPBinURLPrefix +"close-on-response")
-letbackpressurePromise=self.defaultClient.eventLoopGroup.next().makePromise(of:Void.self)
-
-letresultFuture=self.defaultClient.execute(
- request: request, delegate:DelayOnHeadDelegate(promise: backpressurePromise)
-)
-
-self.defaultClient.eventLoopGroup.next().scheduleTask(in:.milliseconds(50)){
- backpressurePromise.succeed(())
+letdelegate=DelayOnHeadDelegate(eventLoop:self.clientGroup.next()){ _, promise in
+ promise.futureResult.eventLoop.scheduleTask(in:.milliseconds(50)){
+ promise.succeed(())
+}
 }
 
+letresultFuture=self.defaultClient.execute(request: request, delegate: delegate)
+
  // The full response must be correctly delivered.
 vardata=try resultFuture.wait()
 guardlet info =try data.readJSONDecodable(RequestInfo.self, length: data.readableBytes)else{
@@ -2920,16 +2918,12 @@ class HTTPClientTests: XCTestCase{
 }
 
 letrequest=tryRequest(url:self.defaultHTTPBinURLPrefix +"close-on-response")
-letbackpressurePromise=self.defaultClient.eventLoopGroup.next().makePromise(of:Void.self)
-
-letresultFuture=self.defaultClient.execute(
- request: request, delegate:DelayOnHeadDelegate(promise: backpressurePromise)
-)
-
-self.defaultClient.eventLoopGroup.next().scheduleTask(in:.milliseconds(50)){
+letdelegate=DelayOnHeadDelegate(eventLoop:self.clientGroup.next()){ _, backpressurePromise in
  backpressurePromise.fail(ExpectedError.expected)
 }
 
+letresultFuture=self.defaultClient.execute(request: request, delegate: delegate)
+
  // The task must be failed.
 XCTAssertThrowsError(try resultFuture.wait()){ error in
 XCTAssertEqual(error as?ExpectedError,.expected)