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/imgutils/gif_test.go

@@ -0,0 +1,89 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package imgutils
+
+import (
+	"bytes"
+	"image"
+	_ "image/gif"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/mattermost/mattermost-server/v6/server/channels/utils/fileutils"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func readTestFile(t *testing.T, name string) ([]byte, error) {
+	t.Helper()
+	path, _ := fileutils.FindDir("tests")
+	file, err := os.Open(filepath.Join(path, name))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	data := &bytes.Buffer{}
+	if _, err := io.Copy(data, file); err != nil {
+		return nil, err
+	}
+	return data.Bytes(), nil
+}
+
+func TestGenGIFData(t *testing.T) {
+	data := GenGIFData(600, 400, 1)
+	img, format, err := image.DecodeConfig(bytes.NewReader(data))
+	require.NoError(t, err)
+	require.Equal(t, 600, img.Width)
+	require.Equal(t, 400, img.Height)
+	require.Equal(t, "gif", format)
+}
+
+func TestCountGIFFrames(t *testing.T) {
+	t.Run("should count the frames of a static gif", func(t *testing.T) {
+		gifData := GenGIFData(400, 400, 1)
+
+		count, err := CountGIFFrames(bytes.NewReader(gifData))
+
+		assert.NoError(t, err)
+		assert.Equal(t, 1, count)
+	})
+
+	t.Run("should count the frames of an animated gif", func(t *testing.T) {
+		gifData := GenGIFData(400, 400, 100)
+
+		count, err := CountGIFFrames(bytes.NewReader(gifData))
+
+		assert.NoError(t, err)
+		assert.Equal(t, 100, count)
+	})
+
+	t.Run("should count the frames of an actual animated gif", func(t *testing.T) {
+		b, err := readTestFile(t, "testgif.gif")
+		require.NoError(t, err)
+
+		count, err := CountGIFFrames(bytes.NewReader(b))
+
+		assert.NoError(t, err)
+		assert.Equal(t, 4, count)
+	})
+
+	t.Run("should return an error for a non-gif image", func(t *testing.T) {
+		b, err := readTestFile(t, "test.png")
+		require.NoError(t, err)
+
+		_, err = CountGIFFrames(bytes.NewReader(b))
+
+		assert.Error(t, err)
+	})
+
+	t.Run("should return an error for garbage data", func(t *testing.T) {
+		_, err := CountGIFFrames(bytes.NewReader([]byte("garbage data")))
+
+		assert.Error(t, err)
+	})
+}