test: fix flaky http(s)-set-server-timeout tests

The tests include a callback that might not be invoked but is wrapped in
common.mustCall(). Remove the common.mustCall() wrapper and add a
comment explaining that it should not be added.

Add a new test case that sets the timeout to 1ms and waits for both the
connection handler and the timeout handler to be invoked. This version
keeps the common.mustCall() wrapper intact around the connection handler
(although it's mostly semantic and not necessary for the test as the
test will certainly fail or time out if that handler isn't invoked).

Fixes: nodejs#11768

test/parallel/test-http-set-timeout-server.js

@@ -152,11 +152,12 @@ test(function serverResponseTimeoutWithPipeline(cb) {
 });
 
 test(function idleTimeout(cb) {
-  const server = http.createServer(common.mustCall((req, res) => {
+  // Do not wrap the callback in common.mustCall(). It might not be invoked.
+  const server = http.createServer((req, res) => {
     req.on('timeout', common.mustNotCall());
     res.on('timeout', common.mustNotCall());
     res.end();
-  }));
+  });
   const s = server.setTimeout(50, common.mustCall((socket) => {
     socket.destroy();
     server.close();
@@ -174,3 +175,41 @@ test(function idleTimeout(cb) {
     });
   }));
 });
+
+test(function fastTimeout(cb) {
+  let connectionHandlerInvoked = false;
+  let timeoutHandlerInvoked = false;
+  let connectionSocket;
+
+  function invokeCallbackIfDone() {
+    if (connectionHandlerInvoked && timeoutHandlerInvoked) {
+      connectionSocket.destroy();
+      server.close();
+      cb();
+    }
+  }
+
+  const server = http.createServer(common.mustCall((req, res) => {
+    req.on('timeout', common.mustNotCall());
+    res.on('timeout', common.mustNotCall());
+    res.end();
+    connectionHandlerInvoked = true;
+    invokeCallbackIfDone();
+  }));
+  const s = server.setTimeout(1, common.mustCall((socket) => {
+    connectionSocket = socket;
+    timeoutHandlerInvoked = true;
+    invokeCallbackIfDone();
+  }));
+  assert.ok(s instanceof http.Server);
+  server.listen(common.mustCall(() => {
+    const options = {
+      port: server.address().port,
+      allowHalfOpen: true,
+    };
+    const c = net.connect(options, () => {
+      c.write('GET /1 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      // Keep-Alive
+    });
+  }));
+});

test/parallel/test-https-set-timeout-server.js

@@ -175,13 +175,12 @@ test(function serverResponseTimeoutWithPipeline(cb) {
 });
 
 test(function idleTimeout(cb) {
-  const server = https.createServer(
-    serverOptions,
-    common.mustCall((req, res) => {
-      req.on('timeout', common.mustNotCall());
-      res.on('timeout', common.mustNotCall());
-      res.end();
-    }));
+  // Do not wrap the callback in common.mustCall(). It might not be invoked.
+  const server = https.createServer(serverOptions, (req, res) => {
+    req.on('timeout', common.mustNotCall());
+    res.on('timeout', common.mustNotCall());
+    res.end();
+  });
   const s = server.setTimeout(50, common.mustCall((socket) => {
     socket.destroy();
     server.close();
@@ -200,3 +199,44 @@ test(function idleTimeout(cb) {
     });
   }));
 });
+
+test(function fastTimeout(cb) {
+  let connectionHandlerInvoked = false;
+  let timeoutHandlerInvoked = false;
+  let connectionSocket;
+
+  function invokeCallbackIfDone() {
+    if (connectionHandlerInvoked && timeoutHandlerInvoked) {
+      connectionSocket.destroy();
+      server.close();
+      cb();
+    }
+  }
+
+  const server = https.createServer(serverOptions, common.mustCall(
+    (req, res) => {
+      req.on('timeout', common.mustNotCall());
+      res.on('timeout', common.mustNotCall());
+      res.end();
+      connectionHandlerInvoked = true;
+      invokeCallbackIfDone();
+    }
+  ));
+  const s = server.setTimeout(1, common.mustCall((socket) => {
+    connectionSocket = socket;
+    timeoutHandlerInvoked = true;
+    invokeCallbackIfDone();
+  }));
+  assert.ok(s instanceof https.Server);
+  server.listen(common.mustCall(() => {
+    const options = {
+      port: server.address().port,
+      allowHalfOpen: true,
+      rejectUnauthorized: false
+    };
+    const c = tls.connect(options, () => {
+      c.write('GET /1 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      // Keep-Alive
+    });
+  }));
+});