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/channels/utils/emoji.go

@@ -0,0 +1,60 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func CreateTestGif(t *testing.T, width int, height int) []byte {
+	var buffer bytes.Buffer
+
+	err := gif.Encode(&buffer, image.NewRGBA(image.Rect(0, 0, width, height)), nil)
+	require.NoErrorf(t, err, "failed to create gif: %v", err)
+
+	return buffer.Bytes()
+}
+
+func CreateTestAnimatedGif(t *testing.T, width int, height int, frames int) []byte {
+	var buffer bytes.Buffer
+
+	img := gif.GIF{
+		Image: make([]*image.Paletted, frames),
+		Delay: make([]int, frames),
+	}
+	for i := 0; i < frames; i++ {
+		img.Image[i] = image.NewPaletted(image.Rect(0, 0, width, height), color.Palette{color.Black})
+		img.Delay[i] = 0
+	}
+	err := gif.EncodeAll(&buffer, &img)
+	require.NoErrorf(t, err, "failed to create animated gif: %v", err)
+
+	return buffer.Bytes()
+}
+
+func CreateTestJpeg(t *testing.T, width int, height int) []byte {
+	var buffer bytes.Buffer
+
+	err := jpeg.Encode(&buffer, image.NewRGBA(image.Rect(0, 0, width, height)), nil)
+	require.NoErrorf(t, err, "failed to create jpeg: %v", err)
+
+	return buffer.Bytes()
+}
+
+func CreateTestPng(t *testing.T, width int, height int) []byte {
+	var buffer bytes.Buffer
+
+	err := png.Encode(&buffer, image.NewRGBA(image.Rect(0, 0, width, height)))
+	require.NoErrorf(t, err, "failed to create png: %v", err)
+
+	return buffer.Bytes()
+}