[skip-changelog] testsuite: added mocked serial discovery for integration tests (#2376)

* Added implementation of serial_discovery mock

* Added first mocked integration test

Author: cmaglie

Diff for: go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/arduino/go-properties-orderedmap v1.8.0
 	github.com/arduino/go-timeutils v0.0.0-20171220113728-d1dd9e313b1b
 	github.com/arduino/go-win32-utils v1.0.0
+	github.com/arduino/pluggable-discovery-protocol-handler/v2 v2.1.1
 	github.com/cmaglie/pb v1.0.27
 	github.com/codeclysm/extract/v3 v3.1.1
 	github.com/djherbis/buffer v1.2.0

Diff for: go.sum

@@ -201,6 +201,33 @@ func (cli *ArduinoCLI) convertEnvForExecutils(env map[string]string) []string {
 	return envVars
 }
 
+// InstallMockedSerialDiscovery will replace the already installed serial-discovery
+// with a mocked one.
+func (cli *ArduinoCLI) InstallMockedSerialDiscovery(t *testing.T) {
+	// Build mocked serial-discovery
+	mockDir := FindRepositoryRootPath(t).Join("internal", "integrationtest", "mock_serial_discovery")
+	gobuild, err := executils.NewProcess(nil, "go", "build")
+	require.NoError(t, err)
+	gobuild.SetDirFromPath(mockDir)
+	require.NoError(t, gobuild.Run(), "Building mocked serial-discovery")
+
+	// Install it replacing the current serial discovery
+	mockBin := mockDir.Join("mock_serial_discovery")
+	dataDir := cli.DataDir()
+	require.NotNil(t, dataDir, "data dir missing")
+	serialDiscoveries, err := dataDir.Join("packages", "builtin", "tools", "serial-discovery").ReadDirRecursiveFiltered(
+		nil, paths.AndFilter(
+			paths.FilterNames("serial-discovery"),
+			paths.FilterOutDirectories(),
+		),
+	)
+	require.NoError(t, err, "scanning data dir for serial-discoveries")
+	require.NotEmpty(t, serialDiscoveries, "no serial-discoveries found in data dir")
+	for _, serialDiscovery := range serialDiscoveries {
+		require.NoError(t, mockBin.CopyTo(serialDiscovery), "installing mocked serial discovery to %s", serialDiscovery)
+	}
+}
+
 // RunWithCustomEnv executes the given arduino-cli command with the given custom env and returns the output.
 func (cli *ArduinoCLI) RunWithCustomEnv(env map[string]string, args ...string) ([]byte, []byte, error) {
 	if cli.cliConfigPath != nil {

Diff for: internal/integrationtest/arduino-cli.go

@@ -91,6 +91,44 @@ func TestBoardList(t *testing.T) {
 		MustBeEmpty()
 }
 
+func TestBoardListMock(t *testing.T) {
+	env, cli := integrationtest.CreateArduinoCLIWithEnvironment(t)
+	defer env.CleanUp()
+
+	_, _, err := cli.Run("core", "update-index")
+	require.NoError(t, err)
+
+	cli.InstallMockedSerialDiscovery(t)
+
+	stdout, _, err := cli.Run("board", "list", "--format", "json")
+	require.NoError(t, err)
+
+	// check is a valid json and contains a list of ports
+	requirejson.Contains(t, stdout, `[
+		{
+		  "matching_boards": [
+			{
+			  "name": "Arduino Yún",
+			  "fqbn": "arduino:avr:yun"
+			}
+		  ],
+		  "port": {
+			"address": "/dev/ttyCIAO",
+			"label": "Mocked Serial port",
+			"protocol": "serial",
+			"protocol_label": "Serial",
+			"properties": {
+			  "pid": "0x0041",
+			  "serial": "123456",
+			  "vid": "0x2341"
+			},
+			"hardware_id": "123456"
+		  }
+		}
+	  ]
+	`)
+}
+
 func TestBoardListWithFqbnFilter(t *testing.T) {
 	if os.Getenv("CI") != "" {
 		t.Skip("VMs have no serial ports")

Diff for: internal/integrationtest/board/board_test.go

@@ -0,0 +1 @@
+mock_serial_discovery

Diff for: internal/integrationtest/mock_serial_discovery/.gitignore

@@ -0,0 +1,100 @@
+//
+// This file is part arduino-cli.
+//
+// Copyright 2023 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to modify or
+// otherwise use the software for commercial activities involving the Arduino
+// software without disclosing the source code of your own applications. To purchase
+// a commercial license, send an email to license@arduino.cc.
+//
+
+package main
+
+import (
+	"errors"
+	"os"
+	"time"
+
+	"github.com/arduino/go-properties-orderedmap"
+	discovery "github.com/arduino/pluggable-discovery-protocol-handler/v2"
+)
+
+type mockSerialDiscovery struct {
+	startSyncCount int
+	closeChan      chan<- bool
+}
+
+func main() {
+	dummy := &mockSerialDiscovery{}
+	server := discovery.NewServer(dummy)
+	if err := server.Run(os.Stdin, os.Stdout); err != nil {
+		os.Exit(1)
+	}
+}
+
+// Hello does nothing here...
+func (d *mockSerialDiscovery) Hello(userAgent string, protocol int) error {
+	return nil
+}
+
+// Quit does nothing here...
+func (d *mockSerialDiscovery) Quit() {}
+
+// Stop terminates the discovery loop
+func (d *mockSerialDiscovery) Stop() error {
+	if d.closeChan != nil {
+		d.closeChan <- true
+		close(d.closeChan)
+		d.closeChan = nil
+	}
+	return nil
+}
+
+// StartSync starts the goroutine that generates fake Ports.
+func (d *mockSerialDiscovery) StartSync(eventCB discovery.EventCallback, errorCB discovery.ErrorCallback) error {
+	// Every 5 starts produce an error
+	d.startSyncCount++
+	if d.startSyncCount%5 == 0 {
+		return errors.New("could not start_sync every 5 times")
+	}
+
+	c := make(chan bool)
+	d.closeChan = c
+
+	// Start asynchronous event emitter
+	go func() {
+		var closeChan <-chan bool = c
+
+		// Output initial port state
+		eventCB("add", &discovery.Port{
+			Address:       "/dev/ttyCIAO",
+			AddressLabel:  "Mocked Serial port",
+			Protocol:      "serial",
+			ProtocolLabel: "Serial",
+			HardwareID:    "123456",
+			Properties: properties.NewFromHashmap(map[string]string{
+				"vid":    "0x2341",
+				"pid":    "0x0041",
+				"serial": "123456",
+			}),
+		})
+
+		select {
+		case <-closeChan:
+			return
+		case <-time.After(5 * time.Second):
+			errorCB("unrecoverable error, cannot send more events")
+		}
+
+		<-closeChan
+	}()
+
+	return nil
+}