Merge netsim mig to master (#17241)

* swarm: merged stream-tests migration to develop

* swarm/network: expose simulation RandomUpNode to use in stream tests

* swarm/network: wait for subs in PeerEvents and fix stream.runSyncTest

* swarm: enforce waitkademlia for snapshot tests

* swarm: fixed syncer tests and snapshot_sync_test

* swarm: linting of simulation package

* swarm: address review comments

* swarm/network/stream: fix delivery_test bugs and refactor

* swarm/network/stream: addressed PR comments @janos

* swarm/network/stream: enforce waitKademlia, improve TestIntervals

* swarm/network/stream: TestIntervals not waiting for chunk to be stored

7 files changed, 41 insertions, 15 deletions

diff --git a/swarm/network/simulation/bucket.go b/swarm/network/simulation/bucket.go
index b37afaaa4..ddbedb521 100644
--- a/swarm/network/simulation/bucket.go
+++ b/swarm/network/simulation/bucket.go
@@ -43,7 +43,7 @@ func (s *Simulation) SetNodeItem(id discover.NodeID, key interface{}, value inte
 	s.buckets[id].Store(key, value)
 }
 
-// NodeItems returns a map of items from all nodes that are all set under the
+// NodesItems returns a map of items from all nodes that are all set under the
 // same BucketKey.
 func (s *Simulation) NodesItems(key interface{}) (values map[discover.NodeID]interface{}) {
 	s.mu.RLock()
diff --git a/swarm/network/simulation/connect.go b/swarm/network/simulation/connect.go
index 3fe82052b..3d0f6cb3f 100644
--- a/swarm/network/simulation/connect.go
+++ b/swarm/network/simulation/connect.go
@@ -54,7 +54,7 @@ func (s *Simulation) ConnectToLastNode(id discover.NodeID) (err error) {
 // ConnectToRandomNode connects the node with provieded NodeID
 // to a random node that is up.
 func (s *Simulation) ConnectToRandomNode(id discover.NodeID) (err error) {
-	n := s.randomUpNode(id)
+	n := s.RandomUpNode(id)
 	if n == nil {
 		return ErrNodeNotFound
 	}
@@ -135,7 +135,7 @@ func (s *Simulation) ConnectNodesStar(id discover.NodeID, ids []discover.NodeID)
 	return nil
 }
 
-// ConnectNodesStar connects all nodes in a star topology
+// ConnectNodesStarPivot connects all nodes in a star topology
 // with the center at already set pivot node.
 // If ids argument is nil, all nodes that are up will be connected.
 func (s *Simulation) ConnectNodesStarPivot(ids []discover.NodeID) (err error) {
diff --git a/swarm/network/simulation/events.go b/swarm/network/simulation/events.go
index f9cfadb73..980a9a756 100644
--- a/swarm/network/simulation/events.go
+++ b/swarm/network/simulation/events.go
@@ -18,6 +18,7 @@ package simulation
 
 import (
 	"context"
+	"sync"
 
 	"github.com/ethereum/go-ethereum/p2p/discover"
 
@@ -71,24 +72,32 @@ func (f *PeerEventsFilter) MsgCode(c uint64) *PeerEventsFilter {
 func (s *Simulation) PeerEvents(ctx context.Context, ids []discover.NodeID, filters ...*PeerEventsFilter) <-chan PeerEvent {
 	eventC := make(chan PeerEvent)
 
+	// wait group to make sure all subscriptions to admin peerEvents are established
+	// before this function returns.
+	var subsWG sync.WaitGroup
 	for _, id := range ids {
 		s.shutdownWG.Add(1)
+		subsWG.Add(1)
 		go func(id discover.NodeID) {
 			defer s.shutdownWG.Done()
 
 			client, err := s.Net.GetNode(id).Client()
 			if err != nil {
+				subsWG.Done()
 				eventC <- PeerEvent{NodeID: id, Error: err}
 				return
 			}
 			events := make(chan *p2p.PeerEvent)
 			sub, err := client.Subscribe(ctx, "admin", events, "peerEvents")
 			if err != nil {
+				subsWG.Done()
 				eventC <- PeerEvent{NodeID: id, Error: err}
 				return
 			}
 			defer sub.Unsubscribe()
 
+			subsWG.Done()
+
 			for {
 				select {
 				case <-ctx.Done():
@@ -153,5 +162,7 @@ func (s *Simulation) PeerEvents(ctx context.Context, ids []discover.NodeID, filt
 		}(id)
 	}
 
+	// wait all subscriptions
+	subsWG.Wait()
 	return eventC
 }
diff --git a/swarm/network/simulation/http.go b/swarm/network/simulation/http.go
index 40f13f32d..69ae3baec 100644
--- a/swarm/network/simulation/http.go
+++ b/swarm/network/simulation/http.go
@@ -29,7 +29,7 @@ var (
 	DefaultHTTPSimAddr = ":8888"
 )
 
-//`With`(builder) pattern constructor for Simulation to
+//WithServer implements the builder pattern constructor for Simulation to
 //start with a HTTP server
 func (s *Simulation) WithServer(addr string) *Simulation {
 	//assign default addr if nothing provided
@@ -46,7 +46,12 @@ func (s *Simulation) WithServer(addr string) *Simulation {
 		Addr:    addr,
 		Handler: s.handler,
 	}
-	go s.httpSrv.ListenAndServe()
+	go func() {
+		err := s.httpSrv.ListenAndServe()
+		if err != nil {
+			log.Error("Error starting the HTTP server", "error", err)
+		}
+	}()
 	return s
 }
 
@@ -55,7 +60,7 @@ func (s *Simulation) addSimulationRoutes() {
 	s.handler.POST("/runsim", s.RunSimulation)
 }
 
-// StartNetwork starts all nodes in the network
+// RunSimulation is the actual POST endpoint runner
 func (s *Simulation) RunSimulation(w http.ResponseWriter, req *http.Request) {
 	log.Debug("RunSimulation endpoint running")
 	s.runC <- struct{}{}
diff --git a/swarm/network/simulation/http_test.go b/swarm/network/simulation/http_test.go
index 4d8bf9946..775cf9219 100644
--- a/swarm/network/simulation/http_test.go
+++ b/swarm/network/simulation/http_test.go
@@ -96,7 +96,12 @@ func sendRunSignal(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Request failed: %v", err)
 	}
-	defer resp.Body.Close()
+	defer func() {
+		err := resp.Body.Close()
+		if err != nil {
+			log.Error("Error closing response body", "err", err)
+		}
+	}()
 	log.Debug("Signal sent")
 	if resp.StatusCode != http.StatusOK {
 		t.Fatalf("err %s", resp.Status)
diff --git a/swarm/network/simulation/node.go b/swarm/network/simulation/node.go
index bc433cfd8..784588fa6 100644
--- a/swarm/network/simulation/node.go
+++ b/swarm/network/simulation/node.go
@@ -195,7 +195,7 @@ func (s *Simulation) AddNodesAndConnectStar(count int, opts ...AddNodeOption) (i
 	return ids, nil
 }
 
-//Upload a snapshot
+//UploadSnapshot uploads a snapshot to the simulation
 //This method tries to open the json file provided, applies the config to all nodes
 //and then loads the snapshot into the Simulation network
 func (s *Simulation) UploadSnapshot(snapshotFile string, opts ...AddNodeOption) error {
@@ -203,7 +203,12 @@ func (s *Simulation) UploadSnapshot(snapshotFile string, opts ...AddNodeOption)
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer func() {
+		err := f.Close()
+		if err != nil {
+			log.Error("Error closing snapshot file", "err", err)
+		}
+	}()
 	jsonbyte, err := ioutil.ReadAll(f)
 	if err != nil {
 		return err
@@ -294,7 +299,7 @@ func (s *Simulation) StopNode(id discover.NodeID) (err error) {
 
 // StopRandomNode stops a random node.
 func (s *Simulation) StopRandomNode() (id discover.NodeID, err error) {
-	n := s.randomUpNode()
+	n := s.RandomUpNode()
 	if n == nil {
 		return id, ErrNodeNotFound
 	}
@@ -324,18 +329,18 @@ func init() {
 	rand.Seed(time.Now().UnixNano())
 }
 
-// randomUpNode returns a random SimNode that is up.
+// RandomUpNode returns a random SimNode that is up.
 // Arguments are NodeIDs for nodes that should not be returned.
-func (s *Simulation) randomUpNode(exclude ...discover.NodeID) *adapters.SimNode {
+func (s *Simulation) RandomUpNode(exclude ...discover.NodeID) *adapters.SimNode {
 	return s.randomNode(s.UpNodeIDs(), exclude...)
 }
 
-// randomUpNode returns a random SimNode that is not up.
+// randomDownNode returns a random SimNode that is not up.
 func (s *Simulation) randomDownNode(exclude ...discover.NodeID) *adapters.SimNode {
 	return s.randomNode(s.DownNodeIDs(), exclude...)
 }
 
-// randomUpNode returns a random SimNode from the slice of NodeIDs.
+// randomNode returns a random SimNode from the slice of NodeIDs.
 func (s *Simulation) randomNode(ids []discover.NodeID, exclude ...discover.NodeID) *adapters.SimNode {
 	for _, e := range exclude {
 		var i int
diff --git a/swarm/network/simulation/service.go b/swarm/network/simulation/service.go
index d1cbf1f8b..02e7ad0cc 100644
--- a/swarm/network/simulation/service.go
+++ b/swarm/network/simulation/service.go
@@ -39,7 +39,7 @@ func (s *Simulation) Service(name string, id discover.NodeID) node.Service {
 // RandomService returns a single Service by name on a
 // randomly chosen node that is up.
 func (s *Simulation) RandomService(name string) node.Service {
-	n := s.randomUpNode()
+	n := s.RandomUpNode()
 	if n == nil {
 		return nil
 	}