v8.0 module release (#22975)

https://mattermost.atlassian.net/browse/MM-52079

```release-note
We upgrade the module version to 8.0. The new module path is github.com/mattermost-server/server/v8.
```


Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

server/model/channel_test.go

@@ -0,0 +1,116 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestChannelCopy(t *testing.T) {
+	o := Channel{Id: NewId(), Name: NewId()}
+	ro := o.DeepCopy()
+
+	require.Equal(t, o.Id, ro.Id, "Ids do not match")
+}
+
+func TestChannelPatch(t *testing.T) {
+	p := &ChannelPatch{Name: new(string), DisplayName: new(string), Header: new(string), Purpose: new(string), GroupConstrained: new(bool)}
+	*p.Name = NewId()
+	*p.DisplayName = NewId()
+	*p.Header = NewId()
+	*p.Purpose = NewId()
+	*p.GroupConstrained = true
+
+	o := Channel{Id: NewId(), Name: NewId()}
+	o.Patch(p)
+
+	require.Equal(t, *p.Name, o.Name)
+	require.Equal(t, *p.DisplayName, o.DisplayName)
+	require.Equal(t, *p.Header, o.Header)
+	require.Equal(t, *p.Purpose, o.Purpose)
+	require.Equal(t, *p.GroupConstrained, *o.GroupConstrained)
+}
+
+func TestChannelIsValid(t *testing.T) {
+	o := Channel{}
+
+	require.NotNil(t, o.IsValid())
+
+	o.Id = NewId()
+	require.NotNil(t, o.IsValid())
+
+	o.CreateAt = GetMillis()
+	require.NotNil(t, o.IsValid())
+
+	o.UpdateAt = GetMillis()
+	require.NotNil(t, o.IsValid())
+
+	o.DisplayName = strings.Repeat("01234567890", 20)
+	require.NotNil(t, o.IsValid())
+
+	o.DisplayName = "1234"
+	o.Name = "ZZZZZZZ"
+	require.NotNil(t, o.IsValid())
+
+	o.Name = "zzzzz"
+	require.NotNil(t, o.IsValid())
+
+	o.Type = "U"
+	require.NotNil(t, o.IsValid())
+
+	o.Type = ChannelTypePrivate
+	require.Nil(t, o.IsValid())
+
+	o.Header = strings.Repeat("01234567890", 100)
+	require.NotNil(t, o.IsValid())
+
+	o.Header = "1234"
+	require.Nil(t, o.IsValid())
+
+	o.Purpose = strings.Repeat("01234567890", 30)
+	require.NotNil(t, o.IsValid())
+
+	o.Purpose = "1234"
+	require.Nil(t, o.IsValid())
+
+	o.Purpose = strings.Repeat("0123456789", 25)
+	require.Nil(t, o.IsValid())
+
+	o.Name = "beu8cc6b3jnxfe9r4na9baooma__36atajbs87dqmpym6o8eiy9saa"
+	require.NotNil(t, o.IsValid())
+
+	o.Name = "71b03afcbb2d503d49f87f057549c43db4e19f92"
+	require.NotNil(t, o.IsValid())
+}
+
+func TestChannelPreSave(t *testing.T) {
+	o := Channel{Name: "test"}
+	o.PreSave()
+	o.Etag()
+}
+
+func TestChannelPreUpdate(t *testing.T) {
+	o := Channel{Name: "test"}
+	o.PreUpdate()
+}
+
+func TestGetGroupDisplayNameFromUsers(t *testing.T) {
+	users := make([]*User, 4)
+	users[0] = &User{Username: NewId()}
+	users[1] = &User{Username: NewId()}
+	users[2] = &User{Username: NewId()}
+	users[3] = &User{Username: NewId()}
+
+	name := GetGroupDisplayNameFromUsers(users, true)
+	require.LessOrEqual(t, len(name), ChannelNameMaxLength)
+}
+
+func TestGetGroupNameFromUserIds(t *testing.T) {
+	name := GetGroupNameFromUserIds([]string{NewId(), NewId(), NewId(), NewId(), NewId()})
+
+	require.LessOrEqual(t, len(name), ChannelNameMaxLength)
+}