peerlistaction.go

// Copyright (c) 2019 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package peertest

import (
	"context"
	"fmt"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"go.uber.org/yarpc/api/peer"
	"go.uber.org/yarpc/api/transport"
	"go.uber.org/yarpc/internal/testtime"
)

// ListActionDeps are passed through PeerListActions' Apply methods in order
// to allow the PeerListAction to modify state other than just the PeerList
type ListActionDeps struct {
	Peers map[string]*LightMockPeer
}

// PeerListAction defines actions that can be applied to a PeerList
type PeerListAction interface {
	// Apply runs a function on the PeerList and asserts the result
	Apply(*testing.T, peer.Chooser, ListActionDeps)
}

// StartAction is an action for testing PeerList.Start
type StartAction struct {
	ExpectedErr error
}

// Apply runs "Start" on the peerList and validates the error
func (a StartAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	err := pl.Start()
	assert.Equal(t, a.ExpectedErr, err)
}

// StopAction is an action for testing PeerList.Stop
type StopAction struct {
	ExpectedErr error
}

// Apply runs "Stop" on the peerList and validates the error
func (a StopAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	err := pl.Stop()
	assert.Equal(t, a.ExpectedErr, err, "Stop action expected error %v, got %v", a.ExpectedErr, err)
}

// ChooseMultiAction will run Choose multiple times on the PeerList
// It will assert if there are ANY failures
type ChooseMultiAction struct {
	ExpectedPeers []string
}

// Apply runs "Choose" on the peerList for every ExpectedPeer
func (a ChooseMultiAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	for _, expectedPeer := range a.ExpectedPeers {
		action := ChooseAction{
			ExpectedPeer:        expectedPeer,
			InputContextTimeout: 50 * testtime.Millisecond,
		}
		action.Apply(t, pl, deps)
	}
}

// ChooseAction is an action for choosing a peer from the peerlist
type ChooseAction struct {
	InputContext        context.Context
	InputContextTimeout time.Duration
	InputRequest        *transport.Request
	ExpectedPeer        string
	ExpectedErr         error
}

// Apply runs "Choose" on the peerList and validates the peer && error
func (a ChooseAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	ctx := a.InputContext
	if ctx == nil {
		ctx = context.Background()
	}
	if a.InputContextTimeout != 0 {
		var cancel context.CancelFunc
		ctx, cancel = context.WithTimeout(ctx, a.InputContextTimeout)
		defer cancel()
	}

	p, finish, err := pl.Choose(ctx, a.InputRequest)
	if err == nil {
		finish(nil)
	}

	if a.ExpectedErr != nil {
		// Note that we're not verifying anything about ExpectedPeer here because
		// it being non-empty means that the test itself was invalid. If anything,
		// that should cause a panic, not a test failure. But that validation can
		// be done before you start asserting expectations.
		assert.Nil(t, p)
		assert.Equal(t, a.ExpectedErr, err)
		return
	}

	if assert.NoError(t, err) && assert.NotNil(t, p) {
		assert.Equal(t, a.ExpectedPeer, p.Identifier())
	}
}

// UpdateAction is an action for adding/removing multiple peers on the PeerList
type UpdateAction struct {
	AddedPeerIDs   []string
	RemovedPeerIDs []string
	ExpectedErr    error
}

// Apply runs "Update" on the peer.Chooser after casting it to a peer.List
// and validates the error
func (a UpdateAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	list := pl.(peer.List)

	added := make([]peer.Identifier, 0, len(a.AddedPeerIDs))
	for _, peerID := range a.AddedPeerIDs {
		added = append(added, MockPeerIdentifier(peerID))
	}

	removed := make([]peer.Identifier, 0, len(a.RemovedPeerIDs))
	for _, peerID := range a.RemovedPeerIDs {
		removed = append(removed, MockPeerIdentifier(peerID))
	}

	err := list.Update(
		peer.ListUpdates{
			Additions: added,
			Removals:  removed,
		},
	)
	assert.Equal(t, a.ExpectedErr, err)
}

// ConcurrentAction will run a series of actions in parallel
type ConcurrentAction struct {
	Actions []PeerListAction
	Wait    time.Duration
}

// Apply runs all the ConcurrentAction's actions in goroutines with a delay of `Wait`
// between each action. Returns when all actions have finished executing
func (a ConcurrentAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	var wg sync.WaitGroup

	wg.Add(len(a.Actions))
	for _, action := range a.Actions {
		go func(ac PeerListAction) {
			defer wg.Done()
			ac.Apply(t, pl, deps)
		}(action)

		if a.Wait > 0 {
			testtime.Sleep(a.Wait)
		}
	}

	wg.Wait()
}

// NotifyStatusChangeAction will run the NotifyStatusChange function on a PeerList
// with a specified Peer after changing the peer's ConnectionStatus
type NotifyStatusChangeAction struct {
	// PeerID is a unique identifier to the Peer we want use in the notification
	PeerID string

	// NewConnectionStatus is the new ConnectionStatus of the Peer
	NewConnectionStatus peer.ConnectionStatus

	// Unretained indicates that this notify occurs to a peer that has never been
	// retained on the transport (to test edge cases).
	Unretained bool
}

// Apply will run the NotifyStatusChanged function on the PeerList with the provided Peer
func (a NotifyStatusChangeAction) Apply(t *testing.T, pl peer.Chooser, deps ListActionDeps) {
	plSub := pl.(peer.Subscriber)

	if a.Unretained {
		plSub.NotifyStatusChanged(MockPeerIdentifier(a.PeerID))
		return
	}

	deps.Peers[a.PeerID].PeerStatus.ConnectionStatus = a.NewConnectionStatus

	plSub.NotifyStatusChanged(deps.Peers[a.PeerID])
}

// ApplyPeerListActions runs all the PeerListActions on the PeerList
func ApplyPeerListActions(t *testing.T, pl peer.Chooser, actions []PeerListAction, deps ListActionDeps) {
	for i, action := range actions {
		t.Run(fmt.Sprintf("action #%d: %T", i, action), func(t *testing.T) {
			action.Apply(t, pl, deps)
		})
	}
}