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// 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
}
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