test: add transport layer (#97)

The purpose of transport layer is to abstract the way to send messages and setup connections between peers in a p2p network. The peer discovery is simulated by a hosted server: every peer sends its address to a known server. Once collecting enough peers, respond the whole peers lists to all peers.

Changes:
- Add test.Trasnport interface
- Add test.Transport implementation by golang channel.
- Add test.transport implementation by TCP connection.
- Move LatencyModel to core/test package
- Add Marshaller interface

5 files changed, 9 insertions, 63 deletions

diff --git a/integration_test/latency.go b/integration_test/latency.go
deleted file mode 100644
index 8f06084..0000000
--- a/integration_test/latency.go
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright 2018 The dexon-consensus-core Authors
-// This file is part of the dexon-consensus-core library.
-//
-// The dexon-consensus-core 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 dexon-consensus-core 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 dexon-consensus-core library. If not, see
-// <http://www.gnu.org/licenses/>.
-
-package integration
-
-import (
-	"math/rand"
-	"time"
-)
-
-// LatencyModel defines an interface to randomly decide latency
-// for one operation.
-type LatencyModel interface {
-	Delay() time.Duration
-}
-
-// NormalLatencyModel would return latencies in normal distribution.
-type NormalLatencyModel struct {
-	Sigma float64
-	Mean  float64
-}
-
-// Delay implements LatencyModel interface.
-func (m *NormalLatencyModel) Delay() time.Duration {
-	delay := rand.NormFloat64()*m.Sigma + m.Mean
-	if delay < 0 {
-		delay = m.Sigma / 2
-	}
-	return time.Duration(delay) * time.Millisecond
-}
-
-// FixedLatencyModel return fixed latencies.
-type FixedLatencyModel struct {
-	Latency float64
-}
-
-// Delay implements LatencyModel interface.
-func (m *FixedLatencyModel) Delay() time.Duration {
-	return time.Duration(m.Latency) * time.Millisecond
-}
diff --git a/integration_test/non-byzantine_test.go b/integration_test/non-byzantine_test.go
index 827d2ad..afda9b4 100644
--- a/integration_test/non-byzantine_test.go
+++ b/integration_test/non-byzantine_test.go
@@ -33,11 +33,11 @@ type NonByzantineTestSuite struct {
 
 func (s *NonByzantineTestSuite) TestNonByzantine() {
 	var (
-		networkLatency = &NormalLatencyModel{
+		networkLatency = &test.NormalLatencyModel{
 			Sigma: 20,
 			Mean:  250,
 		}
-		proposingLatency = &NormalLatencyModel{
+		proposingLatency = &test.NormalLatencyModel{
 			Sigma: 30,
 			Mean:  500,
 		}
diff --git a/integration_test/stats_test.go b/integration_test/stats_test.go
index e0be126..8816e8c 100644
--- a/integration_test/stats_test.go
+++ b/integration_test/stats_test.go
@@ -16,8 +16,8 @@ func (s *EventStatsTestSuite) TestCalculate() {
 	// Setup a test with fixed latency in proposing and network,
 	// and make sure the calculated statistics is expected.
 	var (
-		networkLatency   = &FixedLatencyModel{Latency: 100}
-		proposingLatency = &FixedLatencyModel{Latency: 300}
+		networkLatency   = &test.FixedLatencyModel{Latency: 100}
+		proposingLatency = &test.FixedLatencyModel{Latency: 300}
 		req              = s.Require()
 	)
 
diff --git a/integration_test/utils.go b/integration_test/utils.go
index c1eafb7..7371223 100644
--- a/integration_test/utils.go
+++ b/integration_test/utils.go
@@ -10,7 +10,7 @@ import (
 // PrepareValidators setups validators for testing.
 func PrepareValidators(
 	validatorCount int,
-	networkLatency, proposingLatency LatencyModel) (
+	networkLatency, proposingLatency test.LatencyModel) (
 	apps map[types.ValidatorID]*test.App,
 	dbs map[types.ValidatorID]blockdb.BlockDatabase,
 	validators map[types.ValidatorID]*Validator,
diff --git a/integration_test/validator.go b/integration_test/validator.go
index bfe517f..5909b46 100644
--- a/integration_test/validator.go
+++ b/integration_test/validator.go
@@ -68,8 +68,8 @@ type Validator struct {
 	chainID          uint32
 	cons             *core.Consensus
 	gov              core.Governance
-	networkLatency   LatencyModel
-	proposingLatency LatencyModel
+	networkLatency   test.LatencyModel
+	proposingLatency test.LatencyModel
 }
 
 // NewValidator constructs an instance of Validator.
@@ -79,8 +79,8 @@ func NewValidator(
 	db blockdb.BlockDatabase,
 	privateKey crypto.PrivateKey,
 	vID types.ValidatorID,
-	networkLatency LatencyModel,
-	proposingLatency LatencyModel) *Validator {
+	networkLatency test.LatencyModel,
+	proposingLatency test.LatencyModel) *Validator {
 
 	hashes := make(common.Hashes, 0)
 	for vID := range gov.GetValidatorSet() {