MM-26871 Add test for sidebar when moving channels between teams (#15021)

* MM-26871 Add test for sidebar when moving channels between teams

* Change require.NotNil to require.Error

app/channel_test.go

@@ -103,6 +103,7 @@ func TestRemoveAllDeactivatedMembersFromChannel(t *testing.T) {
 }
 
 func TestMoveChannel(t *testing.T) {
+	t.Run("should move channels between teams", func(t *testing.T) {
 		th := Setup(t).InitBasic()
 		defer th.TearDown()
 		var err *model.AppError
@@ -132,7 +133,7 @@ func TestMoveChannel(t *testing.T) {
 		require.Nil(t, err)
 
 		err = th.App.MoveChannel(targetTeam, channel1, th.BasicUser)
-	require.NotNil(t, err, "Should have failed due to mismatched members.")
+		require.Error(t, err, "Should have failed due to mismatched members.")
 
 		_, err = th.App.AddUserToTeam(targetTeam.Id, th.BasicUser2.Id, "")
 		require.Nil(t, err)
@@ -158,7 +159,7 @@ func TestMoveChannel(t *testing.T) {
 		require.Nil(t, err)
 
 		err = th.App.MoveChannel(targetTeam, channel2, th.BasicUser)
-	require.NotNil(t, err, "Should have failed due to mismatched deacivated member.")
+		require.Error(t, err, "Should have failed due to mismatched deacivated member.")
 
 		// Test moving a channel with no members.
 		channel3 := &model.Channel{
@@ -175,6 +176,48 @@ func TestMoveChannel(t *testing.T) {
 
 		err = th.App.MoveChannel(targetTeam, channel3, th.BasicUser)
 		assert.Nil(t, err)
+	})
+
+	t.Run("should remove sidebar entries when moving channels from one team to another", func(t *testing.T) {
+		th := Setup(t).InitBasic()
+		defer th.TearDown()
+
+		sourceTeam := th.CreateTeam()
+		targetTeam := th.CreateTeam()
+		channel := th.CreateChannel(sourceTeam)
+
+		th.LinkUserToTeam(th.BasicUser, sourceTeam)
+		th.LinkUserToTeam(th.BasicUser, targetTeam)
+		th.AddUserToChannel(th.BasicUser, channel)
+
+		// Put the channel in a custom category so that it explicitly exists in SidebarChannels
+		category, err := th.App.CreateSidebarCategory(th.BasicUser.Id, sourceTeam.Id, &model.SidebarCategoryWithChannels{
+			SidebarCategory: model.SidebarCategory{
+				DisplayName: "new category",
+			},
+			Channels: []string{channel.Id},
+		})
+		require.Nil(t, err)
+		require.Equal(t, []string{channel.Id}, category.Channels)
+
+		err = th.App.MoveChannel(targetTeam, channel, th.BasicUser)
+		require.Nil(t, err)
+
+		moved, err := th.App.GetChannel(channel.Id)
+		require.Nil(t, err)
+		require.Equal(t, targetTeam.Id, moved.TeamId)
+
+		// The channel should no longer be on the old team
+		updatedCategory, err := th.App.GetSidebarCategory(category.Id)
+		require.Nil(t, err)
+		assert.Equal(t, []string{}, updatedCategory.Channels)
+
+		// And it should be on the new team instead
+		categories, err := th.App.GetSidebarCategories(th.BasicUser.Id, targetTeam.Id)
+		require.Nil(t, err)
+		require.Equal(t, model.SidebarCategoryChannels, categories.Categories[1].Type)
+		assert.Contains(t, categories.Categories[1].Channels, channel.Id)
+	})
 }
 
 func TestRemoveUsersFromChannelNotMemberOfTeam(t *testing.T) {