Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/boards/utils/callbackqueue_test.go

@@ -0,0 +1,67 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+import (
+	"context"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/mattermost/mattermost-server/v6/server/platform/shared/mlog"
+)
+
+func Test_newChangeNotifier(t *testing.T) {
+	logger := mlog.CreateConsoleTestLogger(false, mlog.LvlDebug)
+
+	t.Run("startup, shutdown", func(t *testing.T) {
+		cn := NewCallbackQueue("test1", 100, 5, logger)
+
+		var callbackCount int32
+		callback := func() error {
+			atomic.AddInt32(&callbackCount, 1)
+			return nil
+		}
+
+		const loops = 500
+		for i := 0; i < loops; i++ {
+			cn.Enqueue(callback)
+			// don't peg the cpu
+			if i%20 == 0 {
+				time.Sleep(time.Millisecond * 1)
+			}
+		}
+
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+		defer cancel()
+		ok := cn.Shutdown(ctx)
+		assert.True(t, ok, "shutdown should return true (no timeout)")
+
+		assert.Equal(t, int32(loops), atomic.LoadInt32(&callbackCount))
+	})
+
+	t.Run("handle panic", func(t *testing.T) {
+		cn := NewCallbackQueue("test2", 100, 5, logger)
+
+		var callbackCount int32
+		callback := func() error {
+			atomic.AddInt32(&callbackCount, 1)
+			panic("oh no!")
+		}
+
+		const loops = 5
+		for i := 0; i < loops; i++ {
+			cn.Enqueue(callback)
+		}
+
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+		defer cancel()
+		ok := cn.Shutdown(ctx)
+		assert.True(t, ok, "shutdown should return true (no timeout)")
+
+		assert.Equal(t, int32(loops), atomic.LoadInt32(&callbackCount))
+	})
+}