MM-23596: Ability to list private channels for team (#14925)

Summary:
store, app, api and go driver support for listing private channels

Ticket Link:
https://mattermost.atlassian.net/browse/MM-23596

api4/channel.go

@@ -27,6 +27,7 @@ func (api *API) InitChannel() {
 
 	api.BaseRoutes.ChannelsForTeam.Handle("", api.ApiSessionRequired(getPublicChannelsForTeam)).Methods("GET")
 	api.BaseRoutes.ChannelsForTeam.Handle("/deleted", api.ApiSessionRequired(getDeletedChannelsForTeam)).Methods("GET")
+	api.BaseRoutes.ChannelsForTeam.Handle("/private", api.ApiSessionRequired(getPrivateChannelsForTeam)).Methods("GET")
 	api.BaseRoutes.ChannelsForTeam.Handle("/ids", api.ApiSessionRequired(getPublicChannelsByIdsForTeam)).Methods("POST")
 	api.BaseRoutes.ChannelsForTeam.Handle("/search", api.ApiSessionRequiredDisableWhenBusy(searchChannelsForTeam)).Methods("POST")
 	api.BaseRoutes.ChannelsForTeam.Handle("/search_archived", api.ApiSessionRequiredDisableWhenBusy(searchArchivedChannelsForTeam)).Methods("POST")
@@ -763,6 +764,32 @@ func getDeletedChannelsForTeam(c *Context, w http.ResponseWriter, r *http.Reques
 	w.Write([]byte(channels.ToJson()))
 }
 
+func getPrivateChannelsForTeam(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireTeamId()
+	if c.Err != nil {
+		return
+	}
+
+	if !c.App.SessionHasPermissionTo(*c.App.Session(), model.PERMISSION_MANAGE_SYSTEM) {
+		c.SetPermissionError(model.PERMISSION_MANAGE_SYSTEM)
+		return
+	}
+
+	channels, err := c.App.GetPrivateChannelsForTeam(c.Params.TeamId, c.Params.Page*c.Params.PerPage, c.Params.PerPage)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	err = c.App.FillInChannelsProps(channels)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	w.Write([]byte(channels.ToJson()))
+}
+
 func getPublicChannelsByIdsForTeam(c *Context, w http.ResponseWriter, r *http.Request) {
 	c.RequireTeamId()
 	if c.Err != nil {

api4/channel_local.go

@@ -24,6 +24,7 @@ func (api *API) InitChannelLocal() {
 
 	api.BaseRoutes.ChannelsForTeam.Handle("", api.ApiLocal(getPublicChannelsForTeam)).Methods("GET")
 	api.BaseRoutes.ChannelsForTeam.Handle("/deleted", api.ApiLocal(getDeletedChannelsForTeam)).Methods("GET")
+	api.BaseRoutes.ChannelsForTeam.Handle("/private", api.ApiLocal(getPrivateChannelsForTeam)).Methods("GET")
 
 	api.BaseRoutes.ChannelByName.Handle("", api.ApiLocal(getChannelByName)).Methods("GET")
 	api.BaseRoutes.ChannelByNameForTeamName.Handle("", api.ApiLocal(getChannelByNameForTeamName)).Methods("GET")

api4/channel_test.go

@@ -735,6 +735,42 @@ func TestGetDeletedChannelsForTeam(t *testing.T) {
 	require.Len(t, channels, 1, "should be one channel per page")
 }
 
+func TestGetPrivateChannelsForTeam(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+	team := th.BasicTeam
+
+	// normal user
+	_, resp := th.Client.GetPrivateChannelsForTeam(team.Id, 0, 100, "")
+	CheckForbiddenStatus(t, resp)
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		channels, resp := c.GetPrivateChannelsForTeam(team.Id, 0, 100, "")
+		CheckNoError(t, resp)
+		// th.BasicPrivateChannel and th.BasicPrivateChannel2
+		require.Len(t, channels, 2, "wrong number of private channels")
+		for _, c := range channels {
+			// check all channels included are private
+			require.Equal(t, model.CHANNEL_PRIVATE, c.Type, "should include private channels only")
+		}
+
+		channels, resp = c.GetPrivateChannelsForTeam(team.Id, 0, 1, "")
+		CheckNoError(t, resp)
+		require.Len(t, channels, 1, "should be one channel per page")
+
+		channels, resp = c.GetPrivateChannelsForTeam(team.Id, 1, 1, "")
+		CheckNoError(t, resp)
+		require.Len(t, channels, 1, "should be one channel per page")
+
+		channels, resp = c.GetPrivateChannelsForTeam(team.Id, 10000, 100, "")
+		CheckNoError(t, resp)
+		require.Empty(t, channels, "should be no channel")
+
+		_, resp = c.GetPrivateChannelsForTeam("junk", 0, 100, "")
+		CheckBadRequestStatus(t, resp)
+	})
+}
+
 func TestGetPublicChannelsForTeam(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()