Fix HTTP pipeline tests to actually wait for each request before sending mock response.

Otherwise, the HTTP client might be destroyed before it has written all data, since the responses have already been received.

In particular this fixes http-test on Win32.

c++/src/kj/compat/http-test.c++

@@ -887,14 +887,15 @@ KJ_TEST("HttpClient pipeline") {
   auto io = kj::setupAsyncIo();
   auto pipe = io.provider->newTwoWayPipe();
 
-  auto readRequestsPromise = pipe.ends[1]->readAllText();
-
-  auto allRequestText =
-      kj::strArray(KJ_MAP(testCase, PIPELINE_TESTS) { return testCase.request.raw; }, "");
-  auto allResponseText =
-      kj::strArray(KJ_MAP(testCase, PIPELINE_TESTS) { return testCase.response.raw; }, "");
-
-  auto writeResponsesPromise = pipe.ends[1]->write(allResponseText.begin(), allResponseText.size());
+  kj::Promise<void> writeResponsesPromise = kj::READY_NOW;
+  for (auto& testCase: PIPELINE_TESTS) {
+    writeResponsesPromise = writeResponsesPromise
+        .then([&]() {
+      return expectRead(*pipe.ends[1], testCase.request.raw);
+    }).then([&]() {
+      return pipe.ends[1]->write(testCase.response.raw.begin(), testCase.response.raw.size());
+    });
+  }
 
   HttpHeaderTable table;
   auto client = newHttpClient(table, *pipe.ends[0]);
@@ -928,9 +929,6 @@ KJ_TEST("HttpClient pipeline") {
   client = nullptr;
   pipe.ends[0]->shutdownWrite();
 
-  auto requests = readRequestsPromise.wait(io.waitScope);
-  KJ_EXPECT(requests == allRequestText, requests);
-
   writeResponsesPromise.wait(io.waitScope);
 }
 
@@ -938,14 +936,15 @@ KJ_TEST("HttpClient parallel pipeline") {
   auto io = kj::setupAsyncIo();
   auto pipe = io.provider->newTwoWayPipe();
 
-  auto readRequestsPromise = pipe.ends[1]->readAllText();
-
-  auto allRequestText =
-      kj::strArray(KJ_MAP(testCase, PIPELINE_TESTS) { return testCase.request.raw; }, "");
-  auto allResponseText =
-      kj::strArray(KJ_MAP(testCase, PIPELINE_TESTS) { return testCase.response.raw; }, "");
-
-  auto writeResponsesPromise = pipe.ends[1]->write(allResponseText.begin(), allResponseText.size());
+  kj::Promise<void> writeResponsesPromise = kj::READY_NOW;
+  for (auto& testCase: PIPELINE_TESTS) {
+    writeResponsesPromise = writeResponsesPromise
+        .then([&]() {
+      return expectRead(*pipe.ends[1], testCase.request.raw);
+    }).then([&]() {
+      return pipe.ends[1]->write(testCase.response.raw.begin(), testCase.response.raw.size());
+    });
+  }
 
   HttpHeaderTable table;
   auto client = newHttpClient(table, *pipe.ends[0]);
@@ -983,9 +982,6 @@ KJ_TEST("HttpClient parallel pipeline") {
   client = nullptr;
   pipe.ends[0]->shutdownWrite();
 
-  auto requests = readRequestsPromise.wait(io.waitScope);
-  KJ_EXPECT(requests == allRequestText, requests);
-
   writeResponsesPromise.wait(io.waitScope);
 }