p2p/discover: deflake UDP tests

p2p/discover/table.go

@@ -87,9 +87,10 @@ func (tab *Table) Lookup(target NodeID) []*Node {
 		reply          = make(chan []*Node, alpha)
 		pendingQueries = 0
 	)
-	// don't query further if we hit the target.
+	// don't query further if we hit the target or ourself.
 	// unlikely to happen often in practice.
 	asked[target] = true
+	asked[tab.self.ID] = true
 
 	tab.mutex.Lock()
 	// update last lookup stamp (for refresh logic)

p2p/discover/table_test.go

@@ -14,6 +14,18 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
+func TestTable_bumpOrAddBucketAssign(t *testing.T) {
+	tab := newTable(nil, NodeID{}, &net.UDPAddr{})
+	for i := 1; i < len(tab.buckets); i++ {
+		tab.bumpOrAdd(randomID(tab.self.ID, i), &net.UDPAddr{})
+	}
+	for i, b := range tab.buckets {
+		if i > 0 && len(b.entries) != 1 {
+			t.Errorf("bucket %d has %d entries, want 1", i, len(b.entries))
+		}
+	}
+}
+
 func TestTable_bumpOrAddPingReplace(t *testing.T) {
 	pingC := make(pingC)
 	tab := newTable(pingC, NodeID{}, &net.UDPAddr{})

p2p/discover/udp.go

@@ -179,10 +179,9 @@ func (t *udp) findnode(to *Node, target NodeID) ([]*Node, error) {
 	nreceived := 0
 	errc := t.pending(to.ID, neighborsPacket, func(r interface{}) bool {
 		reply := r.(*neighbors)
-		for i := 0; i < len(reply.Nodes); i++ {
+		for _, n := range reply.Nodes {
 			nreceived++
-			n := reply.Nodes[i]
-			if n.ID != t.self.ID && n.isValid() {
+			if n.isValid() {
 				nodes = append(nodes, n)
 			}
 		}

p2p/discover/udp_test.go

 package discover
 
 import (
+	"fmt"
 	logpkg "log"
 	"net"
 	"os"
-	"reflect"
 	"testing"
 	"time"
 
@@ -53,16 +53,37 @@ func TestUDP_findnode(t *testing.T) {
 	defer n1.Close()
 	defer n2.Close()
 
-	entry := MustParseNode("enode://9d8a19597e312ef32d76e6b4903bb43d7bcd892d17b769d30b404bd3a4c2dca6c86184b17d0fdeeafe3b01e0e912d990ddc853db3f325d5419f31446543c30be@127.0.0.1:54194")
-	n2.add([]*Node{entry})
-
+	// put a few nodes into n2. the exact distribution shouldn't
+	// matter much, altough we need to take care not to overflow
+	// any bucket.
 	target := randomID(n1.self.ID, 100)
+	nodes := &nodesByDistance{target: target}
+	for i := 0; i < bucketSize; i++ {
+		n2.add([]*Node{&Node{
+			IP:       net.IP{1, 2, 3, byte(i)},
+			DiscPort: i + 2,
+			TCPPort:  i + 2,
+			ID:       randomID(n2.self.ID, i+2),
+		}})
+	}
+	n2.add(nodes.entries)
+	n2.bumpOrAdd(n1.self.ID, &net.UDPAddr{IP: n1.self.IP, Port: n1.self.DiscPort})
+	expected := n2.closest(target, bucketSize)
+
+	err := runUDP(10, func() error {
 		result, _ := n1.net.findnode(n2.self, target)
-	if len(result) != 1 {
-		t.Fatalf("wrong number of results: got %d, want 1", len(result))
+		if len(result) != bucketSize {
+			return fmt.Errorf("wrong number of results: got %d, want %d", len(result), bucketSize)
+		}
+		for i := range result {
+			if result[i].ID != expected.entries[i].ID {
+				return fmt.Errorf("result mismatch at %d:\n  got:  %v\n  want: %v", i, result[i], expected.entries[i])
 			}
-	if !reflect.DeepEqual(result[0], entry) {
-		t.Errorf("wrong result: got %v, want %v", result[0], entry)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Error(err)
 	}
 }
 
@@ -101,6 +122,7 @@ func TestUDP_findnodeMultiReply(t *testing.T) {
 	defer n1.Close()
 	defer n2.Close()
 
+	err := runUDP(10, func() error {
 		nodes := make([]*Node, bucketSize)
 		for i := range nodes {
 			nodes[i] = &Node{
@@ -113,13 +135,15 @@ func TestUDP_findnodeMultiReply(t *testing.T) {
 
 		// ask N2 for neighbors. it will send an empty reply back.
 		// the request will wait for up to bucketSize replies.
-	resultC := make(chan []*Node)
+		resultc := make(chan []*Node)
+		errc := make(chan error)
 		go func() {
 			ns, err := n1.net.findnode(n2.self, n1.self.ID)
 			if err != nil {
-			t.Error("findnode error:", err)
+				errc <- err
+			} else {
+				resultc <- ns
 			}
-		resultC <- ns
 		}()
 
 		// send a few more neighbors packets to N1.
@@ -138,12 +162,17 @@ func TestUDP_findnodeMultiReply(t *testing.T) {
 		// check that they are all returned. we cannot just check for
 		// equality because they might not be returned in the order they
 		// were sent.
-	result := <-resultC
+		var result []*Node
+		select {
+		case result = <-resultc:
+		case err := <-errc:
+			return err
+		}
 		if hasDuplicates(result) {
-		t.Error("result slice contains duplicates")
+			return fmt.Errorf("result slice contains duplicates")
 		}
 		if len(result) != len(nodes) {
-		t.Errorf("wrong number of nodes returned: got %d, want %d", len(result), len(nodes))
+			return fmt.Errorf("wrong number of nodes returned: got %d, want %d", len(result), len(nodes))
 		}
 		matched := make(map[NodeID]bool)
 		for _, n := range result {
@@ -154,6 +183,29 @@ func TestUDP_findnodeMultiReply(t *testing.T) {
 			}
 		}
 		if len(matched) != len(nodes) {
-		t.Errorf("wrong number of matching nodes: got %d, want %d", len(matched), len(nodes))
+			return fmt.Errorf("wrong number of matching nodes: got %d, want %d", len(matched), len(nodes))
 		}
+		return nil
+	})
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+// runUDP runs a test n times and returns an error if the test failed
+// in all n runs. This is necessary because UDP is unreliable even for
+// connections on the local machine, causing test failures.
+func runUDP(n int, test func() error) error {
+	errcount := 0
+	errors := ""
+	for i := 0; i < n; i++ {
+		if err := test(); err != nil {
+			errors += fmt.Sprintf("\n#%d: %v", i, err)
+			errcount++
+		}
+	}
+	if errcount == n {
+		return fmt.Errorf("failed on all %d iterations:%s", n, errors)
+	}
+	return nil
 }