p2p/protocols, p2p/testing: protocol abstraction and testing

1 files changed, 206 insertions, 0 deletions

diff --git a/p2p/testing/protocolsession.go b/p2p/testing/protocolsession.go
new file mode 100644
index 000000000..a779aeebb
--- /dev/null
+++ b/p2p/testing/protocolsession.go
@@ -0,0 +1,206 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package testing
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/discover"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+)
+
+// ProtocolSession is a quasi simulation of a pivot node running
+// a service and a number of dummy peers that can send (trigger) or
+// receive (expect) messages
+type ProtocolSession struct {
+	Server  *p2p.Server
+	IDs     []discover.NodeID
+	adapter *adapters.SimAdapter
+	events  chan *p2p.PeerEvent
+}
+
+// Exchange is the basic units of protocol tests
+// the triggers and expects in the arrays are run immediately and asynchronously
+// thus one cannot have multiple expects for the SAME peer with DIFFERENT message types
+// because it's unpredictable which expect will receive which message
+// (with expect #1 and #2, messages might be sent #2 and #1, and both expects will complain about wrong message code)
+// an exchange is defined on a session
+type Exchange struct {
+	Label    string
+	Triggers []Trigger
+	Expects  []Expect
+}
+
+// Trigger is part of the exchange, incoming message for the pivot node
+// sent by a peer
+type Trigger struct {
+	Msg     interface{}     // type of message to be sent
+	Code    uint64          // code of message is given
+	Peer    discover.NodeID // the peer to send the message to
+	Timeout time.Duration   // timeout duration for the sending
+}
+
+// Expect is part of an exchange, outgoing message from the pivot node
+// received by a peer
+type Expect struct {
+	Msg     interface{}     // type of message to expect
+	Code    uint64          // code of message is now given
+	Peer    discover.NodeID // the peer that expects the message
+	Timeout time.Duration   // timeout duration for receiving
+}
+
+// Disconnect represents a disconnect event, used and checked by TestDisconnected
+type Disconnect struct {
+	Peer  discover.NodeID // discconnected peer
+	Error error           // disconnect reason
+}
+
+// trigger sends messages from peers
+func (self *ProtocolSession) trigger(trig Trigger) error {
+	simNode, ok := self.adapter.GetNode(trig.Peer)
+	if !ok {
+		return fmt.Errorf("trigger: peer %v does not exist (1- %v)", trig.Peer, len(self.IDs))
+	}
+	mockNode, ok := simNode.Services()[0].(*mockNode)
+	if !ok {
+		return fmt.Errorf("trigger: peer %v is not a mock", trig.Peer)
+	}
+
+	errc := make(chan error)
+
+	go func() {
+		errc <- mockNode.Trigger(&trig)
+	}()
+
+	t := trig.Timeout
+	if t == time.Duration(0) {
+		t = 1000 * time.Millisecond
+	}
+	select {
+	case err := <-errc:
+		return err
+	case <-time.After(t):
+		return fmt.Errorf("timout expecting %v to send to peer %v", trig.Msg, trig.Peer)
+	}
+}
+
+// expect checks an expectation of a message sent out by the pivot node
+func (self *ProtocolSession) expect(exp Expect) error {
+	if exp.Msg == nil {
+		return errors.New("no message to expect")
+	}
+	simNode, ok := self.adapter.GetNode(exp.Peer)
+	if !ok {
+		return fmt.Errorf("trigger: peer %v does not exist (1- %v)", exp.Peer, len(self.IDs))
+	}
+	mockNode, ok := simNode.Services()[0].(*mockNode)
+	if !ok {
+		return fmt.Errorf("trigger: peer %v is not a mock", exp.Peer)
+	}
+
+	errc := make(chan error)
+	go func() {
+		errc <- mockNode.Expect(&exp)
+	}()
+
+	t := exp.Timeout
+	if t == time.Duration(0) {
+		t = 2000 * time.Millisecond
+	}
+	select {
+	case err := <-errc:
+		return err
+	case <-time.After(t):
+		return fmt.Errorf("timout expecting %v sent to peer %v", exp.Msg, exp.Peer)
+	}
+}
+
+// TestExchanges tests a series of exchanges against the session
+func (self *ProtocolSession) TestExchanges(exchanges ...Exchange) error {
+	// launch all triggers of this exchanges
+
+	for _, e := range exchanges {
+		errc := make(chan error, len(e.Triggers)+len(e.Expects))
+		for _, trig := range e.Triggers {
+			errc <- self.trigger(trig)
+		}
+
+		// each expectation is spawned in separate go-routine
+		// expectations of an exchange are conjunctive but unordered, i.e.,
+		// only all of them arriving constitutes a pass
+		// each expectation is meant to be for a different peer, otherwise they are expected to panic
+		// testing of an exchange blocks until all expectations are decided
+		// an expectation is decided if
+		//  expected message arrives OR
+		// an unexpected message arrives (panic)
+		// times out on their individual timeout
+		for _, ex := range e.Expects {
+			// expect msg spawned to separate go routine
+			go func(exp Expect) {
+				errc <- self.expect(exp)
+			}(ex)
+		}
+
+		// time out globally or finish when all expectations satisfied
+		timeout := time.After(5 * time.Second)
+		for i := 0; i < len(e.Triggers)+len(e.Expects); i++ {
+			select {
+			case err := <-errc:
+				if err != nil {
+					return fmt.Errorf("exchange failed with: %v", err)
+				}
+			case <-timeout:
+				return fmt.Errorf("exchange %v: '%v' timed out", i, e.Label)
+			}
+		}
+	}
+	return nil
+}
+
+// TestDisconnected tests the disconnections given as arguments
+// the disconnect structs describe what disconnect error is expected on which peer
+func (self *ProtocolSession) TestDisconnected(disconnects ...*Disconnect) error {
+	expects := make(map[discover.NodeID]error)
+	for _, disconnect := range disconnects {
+		expects[disconnect.Peer] = disconnect.Error
+	}
+
+	timeout := time.After(time.Second)
+	for len(expects) > 0 {
+		select {
+		case event := <-self.events:
+			if event.Type != p2p.PeerEventTypeDrop {
+				continue
+			}
+			expectErr, ok := expects[event.Peer]
+			if !ok {
+				continue
+			}
+
+			if !(expectErr == nil && event.Error == "" || expectErr != nil && expectErr.Error() == event.Error) {
+				return fmt.Errorf("unexpected error on peer %v. expected '%v', got '%v'", event.Peer, expectErr, event.Error)
+			}
+			delete(expects, event.Peer)
+		case <-timeout:
+			return fmt.Errorf("timed out waiting for peers to disconnect")
+		}
+	}
+	return nil
+}